Fractal Theory and Field Cover Experiments: Implications for the Fractal Characteristics and Radon Diffusion Behavior of Soils and Rocks
作者：
Tan, Wanyu;Li, Yongmei;Tan, Kaixuan* ;Duan, Xianzhe;Liu, Dong;...
期刊：
HEALTH PHYSICS ,2016年111(6):506-512 ISSN：0017-9078
通讯作者：
Tan, Kaixuan
作者机构：
[Li, Yongmei; Liu, Zehua; Tan, Wanyu; Tan, Kaixuan; Duan, Xianzhe; Liu, Dong] Univ South China, Sch Nucl Resources Engn, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Tan, Kaixuan] U;Univ South China, Sch Nucl Resources Engn, Hengyang 421001, Hunan, Peoples R China.
关键词：
diffusion;radon;soil;uranium
摘要：
Radon diffusion and transport through different media is a complex process affected by many factors. In this study, the fractal theories and field covering experiments were used to study the fractal characteristics of particle size distribution (PSD) of six kinds of geotechnical materials (e.g., waste rock, sand, laterite, kaolin, mixture of sand and laterite, and mixture of waste rock and laterite) and their effects on radon diffusion. In addition, the radon diffusion coefficient and diffusion length were calculated. Moreover, new formulas for estimating diffusion coefficient and diffusion length functional of fractal dimension d of PSD were proposed. These results demonstrate the following points: (1) the fractal dimension d of the PSD can be used to characterize the property of soils and rocks in the studies of radon diffusion behavior; (2) the diffusion coefficient and diffusion length decrease with increasing fractal dimension of PSD; and (3) the effectiveness of final covers in reducing radon exhalation of uranium tailings impoundments can be evaluated on the basis of the fractal dimension of PSD of materials.
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英文
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Bioreduction of U(VI) and stability of immobilized uranium under suboxic conditions
作者：
Hu, Nan;Ding, De-xin* ;Li, Shi-mi;Tan, Xiang;Li, Guang-yue;...
期刊：
Journal of Environmental Radioactivity ,2016年154:60-67 ISSN：0265-931X
通讯作者：
Ding, De-xin
作者机构：
[Li, Shi-mi; Li, Guang-yue; Hu, Nan; Tan, Xiang; Ding, De-xin; Xu, Fei; Wang, Yong-dong] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, 28 West Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Ding, De-xin] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, 28 West Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
关键词：
Biogenic U(IV);Biostimulation;Reoxidation;Suboxic conditions;U(VI) bioreduction
摘要：
In order to study the bioreduction of U(VI) and stability of immobilized uranium under suboxic conditions, microcosm were amended with ethanol, lactate and glucose, and incubated under suboxic conditions. During the incubation, total dissolved U in amended microcosms decreased from 0.95 mg/L to 0.03 mg/L. Pyrosequencing results showed that, the proportion of anaerobic microorganisms capable of reducing U(VI) under suboxic conditions was small compared with that under anoxic conditions;the proportion of aerobic and facultative anaerobic microorganisms capable of consuming the dissolved oxygen was large;and some of the facultative anaerobic microorganisms could reduce U(VI). These results indicated that different microbial communities were responsible for the bioreduction of U(VI) under suboxic and anoxic conditions. After the electron donors were exhausted, total dissolved U in the amended microcosms remained unchanged, while the U(VI)/U(IV) ratio in the solid phase of sediments increased obviously. This implied that the performance of bioreduction of the U(VI) can be maintained under suboxic condition. Different microbial communities were responsible for the bioreduction of U(VI) under suboxic and anoxic conditions. ©2016 Elsevier Ltd.
语种：
英文
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Proteomics analysis of liver tissues from C57BL/6J mice receiving low-dose 137Cs radiation
作者：
Yi, Lan;Li, Linwei;Yin, Jie;Hu, Nan;Li, Guangyue;...
期刊：
Environmental Science and Pollution Research ,2016年23(3):2549-2556 ISSN：0944-1344
通讯作者：
Ding, Dexin
作者机构：
[Ding, Dexin; Yin, Jie; Yi, Lan; Li, Guangyue; Hu, Nan] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.;[Yin, Jie; Yi, Lan; Li, Linwei] Univ South China, Coll Pharm & Biol Sci, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Ding, Dexin] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.
关键词：
Low-dose irradiation;Proteomics;C57BL/6EJ mice;CAT;GNMT;GSTP1
摘要：
Differentially expressed proteins in liver tissues of C57BL/6J mice receiving low-dose 137Cs radiation were examined by proteomics analysis. Compared with the control group, 80 proteins were differentially expressed in the irradiated group. Among the 40 randomly selected proteins used for peptide mass fingerprinting analysis and bioinformatics, 24 were meaningful. These proteins were related to antioxidant defense, amino acid metabolism, detoxification, anti-tumor development, amino acid transport, anti-peroxidation, and composition of respiratory chain. Western blot analysis showed that catalase (CAT), glycine N-methyltransferase (GNMT), and glutathione S-transferase P1 (GSTP1) were up-regulated in the irradiated group; these results were in agreement with qPCR results. These results show that CAT, GNMT, and GSTP1 may be related to stress response induced by low-dose irradiation in mice liver. The underlying mechanism however requires further investigation. © 2015, Springer-Verlag Berlin Heidelberg.
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英文
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Developmental toxicity and oxidative stress induced by gamma irradiation in zebrafish embryos
作者：
Hu, Miao;Hu, Nan;Ding, Dexin* ;Zhao, Weichao;Feng, Yongfu;...
期刊：
Radiation and Environmental Biophysics ,2016年55(4):441-450 ISSN：0301-634X
通讯作者：
Ding, Dexin
作者机构：
[Ding, Dexin; Hu, Miao; Zhang, Hui; Feng, Yongfu; Li, Guangyue; Hu, Nan; Wang, Yongdong; Zhao, Weichao] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Ding, Dexin] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.
关键词：
Gamma irradiation;Zebrafish embryo;Oxidative stress;Developmental toxicity;Biomarker
摘要：
This study aimed to evaluate the biological effects of gamma irradiation on zebrafish embryos. Different doses of gamma rays (0.01, 0.05, 0.1, 0.5 and 1 Gy) were used to irradiate zebrafish embryos at three developmental stages (stage 1, 6 h post-fertilization (hpf); stage 2, 12 hpf; stage three, 24 hpf), respectively. The survival, malformation and hatching rates of the zebrafish embryos were measured at the morphological endpoint of 96 hpf. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx) and glutathione S-transferase (GST) were assayed. Morphology analysis showed that gamma irradiation inhibited hatching and induced developmental toxicity in a dose-dependent manner. Interestingly, after irradiation the malformation rate changed not only in a dose-dependent manner but also in a developmental stage-dependent manner, indicating that the zebrafish embryos at stage 1 were more sensitive to gamma rays than those at other stages. Biochemical analysis showed that gamma irradiation modulated the activities of antioxidant enzymes in a dose-dependent manner. A linear relationship was found between GPx activity and irradiation dose in 0.1–1 Gy group, and GPx was a suitable biomarker for gamma irradiation in the dose range from 0.1 to 1 Gy. Furthermore, the activities of SOD, CAT, GR and GPx of the zebrafish embryos at stage 3 were found to be much higher than those at other stages, indicating that the zebrafish embryos at stage 3 had a greater ability to protect against gamma rays than those at other stages, and thus the activities of antioxidant enzymes changed in a developmental stage-dependent manner.
语种：
英文
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Modeling and experimental examination of water level effects on radon exhalation from fragmented uranium ore
作者：
Ye, Yong-jun* ;Dai, Xin-tao;Ding, De-xin;Zhao, Ya-li
期刊：
Journal of Environmental Radioactivity ,2016年165:219-226 ISSN：0265-931X
通讯作者：
Ye, Yong-jun
作者机构：
[Ye, Yong-jun; Ding, De-xin] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.;[Dai, Xin-tao; Ye, Yong-jun; Zhao, Ya-li] Univ South China, Sch Environm Protect & Safety Engn, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Ye, Yong-jun] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.
关键词：
Model;Fragmented uranium ore;Water level;Radon concentration;Radon exhalation rate
摘要：
In this study, a one-dimensional steady-state mathematical model of radon transport in fragmented uranium ore was established according to Fick's law and radon transfer theory in an air-water interface. The model was utilized to obtain an analytical solution for radon concentration in the air-water, two-phase system under steady state conditions, as well as a corresponding radon exhalation rate calculation formula. We also designed a one-dimensional experimental apparatus for simulating radon diffusion migration in the uranium ore with various water levels to verify the mathematical model. The predicted results were in close agreement with the measured results, suggesting that the proposed model can be readily used to determine radon concentrations and exhalation rates in fragmented uranium ore with varying water levels.
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英文
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Insights into the fluoride-resistant regulation mechanism of Acidithiobacillus ferrooxidans ATCC 23270 based on whole genome microarrays
作者：
Ma, Liyuan;Li, Qian;Shen, Li;Feng, Xue;Xiao, Yunhua;...
期刊：
Journal of Industrial Microbiology & Biotechnology ,2016年43(10):1441-1453 ISSN：1367-5435
通讯作者：
Liu, Xueduan
作者机构：
[Feng, Xue; Yin, Huaqun; Liu, Xueduan; Xiao, Yunhua; Liang, Yili; Shen, Li; Ma, Liyuan; Tao, Jiemeng] Cent S Univ, Sch Minerals Proc & Bioengn, Changsha 410083, Hunan, Peoples R China.;[Feng, Xue; Yin, Huaqun; Liu, Xueduan; Xiao, Yunhua; Liang, Yili; Shen, Li; Ma, Liyuan; Tao, Jiemeng] Minist Educ, Key Lab Biomet, Changsha, Hunan, Peoples R China.;[Li, Qian] Univ South China, Sch Nucl Resources Engn, Hengyang, Peoples R China.;[Li, Qian] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang, Peoples R China.
通讯机构：
[Liu, Xueduan] C;[Liu, Xueduan] M;Cent S Univ, Sch Minerals Proc & Bioengn, Changsha 410083, Hunan, Peoples R China.;Minist Educ, Key Lab Biomet, Changsha, Hunan, Peoples R China.
关键词：
Fluoride;A. ferrooxidans ATCC 23270;Whole genome microarray;Expression profiling
摘要：
Acidophilic microorganisms involved in uranium bioleaching are usually suppressed by dissolved fluoride ions, eventually leading to reduced leaching efficiency. However, little is known about the regulation mechanisms of microbial resistance to fluoride. In this study, the resistance of Acidithiobacillus ferrooxidans ATCC 23270 to fluoride was investigated by detecting bacterial growth fluctuations and ferrous or sulfur oxidation. To explore the regulation mechanism, a whole genome microarray was used to profile the genome-wide expression. The fluoride tolerance of A. ferrooxidans cultured in the presence of FeSO4 was better than that cultured with the S0 substrate. The differentially expressed gene categories closely related to fluoride tolerance included those involved in energy metabolism, cellular processes, protein synthesis, transport, the cell envelope, and binding proteins. This study highlights that the cellular ferrous oxidation ability was enhanced at the lower fluoride concentrations. An overview of the cellular regulation mechanisms of extremophiles to fluoride resistance is discussed.
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英文
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Hydrogen sulfide (H2S) attenuates uranium-induced acute nephrotoxicity through oxidative stress and inflammatory response via Nrf2-NF-κB pathways
作者：
Zheng, Jifang;Zhao, Tingting;Yuan, Yan;Hu, Nan;Tang, Xiaoqing*
期刊：
Chemico-Biological Interactions ,2015年242:353-362 ISSN：0009-2797
通讯作者：
Tang, Xiaoqing
作者机构：
[Zheng, Jifang; Yuan, Yan; Zhao, Tingting] Univ South China, Pharm & Life Coll, Inst Biol, Hengyang City 421001, Hunan, Peoples R China.;[Tang, Xiaoqing] Univ South China, Coll Med, Inst Neurosci, Hengyang City 421001, Hunan, Peoples R China.;[Hu, Nan] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang City 421001, Hunan, Peoples R China.;[Tang, Xiaoqing] Univ South China, Coll Med, Inst Neurosci, Changsheng West Rd 28, Hengyang City 421001, Hunan, Peoples R China.
通讯机构：
[Tang, Xiaoqing] U;Univ South China, Coll Med, Inst Neurosci, Changsheng West Rd 28, Hengyang City 421001, Hunan, Peoples R China.
关键词：
Hydrogen sulfide (H(2)S);NF-kappaB;Nephrotoxicity;Nrf2;Oxidative stress;Uranium
摘要：
As an endogenous gaseous mediator, H2S exerts anti-oxidative, anti-inflammatory and cytoprotective effects in kidneys. This study was designed to investigate the protective effect of H2S against uranium-induced nephrotoxicity in adult SD male rats after in vivo effect of uranium on endogenous H2S formation was explored in kidneys. The levels of endogenous H2S and H2S-producing enzymes (CBS and CSE) were measured in renal homogenates from rats intoxicated by an intraperitoneally (i.p.) injection of uranyl acetate at a single dose of 2.5, 5 or 10 mg/kg. In rats injected i.p. with uranyl acetate (5 mg/kg) or NaHS (an H2S donor, 28 or 56 μmol/kg) alone or in combination, we determined biochemical parameters and histopathological alteration to assess kidney function, examined oxidative stress markers, and investigated Nrf2 and NF-κB pathways in kidney homogenates. The results suggest that uranium intoxication in rats decreased endogenous H2S generation as well as CBS and CSE protein expression. NaHS administration in uranium-intoxicated rats ameliorated the renal biochemical indices and histopathological effects, lowered MDA accumulation, and restored GSH level and anti-oxidative enzymes activities like SOD, CAT, GPx and GST. NaHS treatment in uranium-intoxicated rats activated uranium-inhibited protein expression and nuclear translocation of transcription factor Nrf2, which increased protein expression of downstream target-Nrf2 genes HO-1, NQO-1, GCLC, and TXNRD-1. NaHS administration in uranium-intoxicated rats inhibited uranium-induced nuclear translocation and phosphorylation of transcription factor κB/p65, which decreased protein expression of target-p65 inflammatory genes TNF-α, iNOS, and COX-2. Taken together, these data implicate that H2S can afford protection to rat kidneys against uranium-induced adverse effects through induction of antioxidant defense by activating Nrf2 pathway and reduction of inflammatory response by suppressing NF-κB pathway. © 2015 Elsevier Ireland Ltd.
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英文
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An artificially constructed Syngonium podophyllum-Aspergillus niger combinate system for removal of uranium from wastewater
作者：
He, Jia-dong;Wang, Yong-dong;Hu, Nan;Ding, Dexin* ;Sun, Jing;...
期刊：
Environmental Science and Pollution Research ,2015年22(23):18918-18926 ISSN：0944-1344
通讯作者：
Ding, Dexin
作者机构：
[Ding, Dexin; He, Jia-dong; Li, Chang-wu; Hu, Nan; Sun, Jing; Deng, Qin-wen; Xu, Fei; Wang, Yong-dong] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.;[Ding, Dexin] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, 28 West Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Ding, Dexin] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, 28 West Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
关键词：
Aspergillus niger;Syngonium podophyllum;Combinate system;Uranium wastewater;Phytoremediation
摘要：
Aspergillus niger was inoculated to the roots of five plants, and the Syngonium podophyllum-A. niger combinate system (SPANCS) was found to be the most effective in removing uranium from hydroponic liquid with initial uranium concentration of 5 mg L−1. Furthermore, the hydroponic experiments on the removal of uranium from the hydroponic liquids with initial uranium concentrations of 0.5, 1.0, and 3.0 mg L−1 by the SPANCS were conducted, the inhibitory effect of A. niger on the growth of S. podophyllum in the SPANCS was studied, the accumulation characteristics of uranium by S. podophyllum in the SPANCS were analyzed, and the Fourier transform infrared (FT-IR) and extended X-ray absorption fine structure (EXAFS) spectra were measured. The results show that the removal of uranium by the SPANCS from the hydroponic liquids with initial uranium concentrations of 0.5, 1.0, and 3.0 mg L−1 reached 98.20, 97.90, and 98.50 %, respectively, after 37 days of accumulation of uranium; that the uranium concentrations in the hydroponic liquids decreased to 0.009, 0.021, and 0.045 mg L−1, respectively, which are lower than the stipulated concentration for discharge of 0.050 mg L−1 by the People’s Republic of China; that A. niger helped to generate more groups in the root of S. podophyllum which can improve the complexing capability of S. podophyllum for uranium; and that the uranium accumulated in the root of S. podophyllum was in the form of phosphate uranyl and carboxylic uranyl. © 2015, Springer-Verlag Berlin Heidelberg.
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英文
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Bioreduction of U(VI) in groundwater under anoxic conditions from a decommissioned in situ leaching uranium mine
作者：
Ding, De-xin* ;Li, Shi-mi;Hu, Nan;Xu, Fei;Li, Guang-yue;...
期刊：
Bioprocess and Biosystems Engineering ,2015年38(4):661-669 ISSN：1615-7591
通讯作者：
Ding, De-xin
作者机构：
[Li, Shi-mi; Li, Guang-yue; Hu, Nan; Ding, De-xin; Xu, Fei; Wang, Yong-dong] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.;[Ding, De-xin] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, 28 West Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Ding, De-xin] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, 28 West Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
关键词：
In situ leaching;Groundwater;Bioreduction;U(VI);Anaerobic zone
摘要：
To determine whether the U(VI) in groundwater under anoxic conditions at a decommissioned in situ leaching (ISL) uranium mine could be bioreduced, groundwater samples containing suspended sediments were taken from the mine, experimental setup was fabricated, and the jar containing the groundwater in the setup was amended with ethanol and incubated under anoxic conditions. The variations of pH, chemical oxygen demand, nitrate, sulfate, U(VI), and dissolved oxygen (DO) concentrations were monitored during the incubation. U(VI) concentration dropped to 0.043 mg/L when the stimulated microorganisms were active, and it then increased to 0.835 mg/L within 10 days after the metabolism of the stimulated microorganisms was inhibited. The DO variation was observed in the amended jar during the incubation, and the metabolism of the stimulated microorganisms was found to affect the DO concentration. Firmicutes were found to be dominant in the sediments in the amended jar through the 16S rRNA pyrosequencing. The results indicate that it is possible to bioreduce U(VI) in the groundwater under anoxic conditions at the decommissioned ISL uranium mine by adding carbon source into it without removing the oxygen from it.
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英文
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Phytoextraction of uranium from contaminated soil by Macleaya cordata before and after application of EDDS and CA
作者：
Li, Chang-wu;Hu, Nan;Ding, De-xin* ;Hu, Jin-song;Li, Guang-yue;...
期刊：
Environmental Science and Pollution Research ,2015年22(8):6155-6163 ISSN：0944-1344
通讯作者：
Ding, De-xin
作者机构：
[Li, Guang-yue; Li, Chang-wu; Hu, Jin-song; Hu, Nan; Ding, De-xin; Wang, Yong-dong] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.;[Ding, De-xin] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, 28 West Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Ding, De-xin] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, 28 West Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
关键词：
Macleaya cordata;Phytoextraction;Uranium;[S,S]-Ethylenediaminedisuccinic acid;Citric acid;Soil solution
摘要：
This is the first report on using Macleaya cordata for phytoextraction of uranium from the uranium contaminated soil in the greenhouse. Macleaya M. cordata was found to increase uranium concentration in the soil solution by increasing the dissolved organic carbon (DOC). The amendment experiments with citric acid (CA) and [S,S]-ethylenediamine disuccinic acid (EDDS) at the rates of 1.0, 2.5, 5.0, and 10.0 mmol kg−1 dry weight (DW) soil showed that EDDS was more efficient to increase uranium concentration in the shoot than CA when they were applied at the same rate. The applications of 5.0 mmol kg−1 EDDS and 10.0 mmol kg−1 CA were most appropriate for increasing uranium concentrations in the shoot of M. cordata. CA was more efficient to increase the solubility of uranium at the same application rates except for 2.5 mmol kg−1 application rate. There was a linear correlation between the uranium concentration in the shoot and the average uranium concentration of one planted pot during 14 days in soil solution after the application of different rates of EDDS and CA, respectively (r2 = 0.972, P < 0.01; r2 = 0.948, P < 0.01), indicating that uranium uptake was dependent on the soluble uranium concentration. The Fe-U-DOC and Mn-U-DOC complexes were probably formed after the application of CA. Soil solution pH and Fe, Mn, Ca, and DOC concentrations in soil solution were found to be changed by the chelates. © 2014, Springer-Verlag Berlin Heidelberg.
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英文
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Vegetation composition and 226 Ra uptake by native plant species at a uranium mill tailings impoundment in South China
作者：
Hu, Nan;Ding, Dexin* ;Li, Guangyue;Zheng, Jifang;Li, Le;...
期刊：
Journal of Environmental Radioactivity ,2014年129:100-106 ISSN：0265-931X
通讯作者：
Ding, Dexin
作者机构：
[Ding, Dexin; Zheng, Jifang; Li, Le; Li, Guangyue; Hu, Nan; Wang, Yongdong; Zhao, Weichao] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Ding, Dexin] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.
关键词：
Hyperaccumulator;Mill tailings impoundment;Phytoremediation;Radium;Uranium;Vegetation composition
摘要：
A field investigation was conducted for the vegetation composition and <sup>226</sup>Ra uptake by native plant species at a uranium mill tailings impoundment in South China. 80 species belonging to 67 genera in 32 families were recorded in the sampling sites. The Poaceae and Asteraceae were the dominant families colonizing the impoundment. The number of the plant species and vegetation community composition in the sampling sites seemed most closely related to the activities of <sup>226</sup>Ra and the pH value of the uranium tailings. The plant species in the sampling sites with relatively low activities of <sup>226</sup>Ra and relatively high pH value formed a relatively stable vegetation community. The plant species in the sampling sites with medium activities of <sup>226</sup>Ra and medium pH value formed the transitional vegetation community. The plant species in the sampling sites with relatively high activities of <sup>226</sup>Ra and relatively low pH value formed a simple unstable vegetation community that was similar to that on the unused grassland. The activities of <sup>226</sup>Ra and transfer factors (TFs) varied greatly with the plant species. The high activities of <sup>226</sup>Ra and TFs were found in the leaves of Pteris multifida (150.6Bq/g of AW;9.131), Pteridium aquilinum (122.2Bq/g of AW;7.409), and Dryopteris scottii (105.7Bq/g of AW;6.408). They satisfied the criteria for a hyperaccumulator for <sup>226</sup>Ra. They may be the candidates for phytoremediation of <sup>226</sup>Ra in the uranium mill tailings impoundment areas and the contaminated soils around. ©2014 Elsevier Ltd.
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英文
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Comprehensive Genomic Characterization of Campylobacter Genus Reveals Some Underlying Mechanisms for its Genomic Diversification
作者：
Zhou, Yizhuang;Bu, Lijing;Guo, Min;Zhou, Chengran;Wang, Yongdong;...
期刊：
PLOS ONE ,2013年8(8):e70241- ISSN：1932-6203
通讯作者：
Chen, Liyu
作者机构：
[Zhou, Yizhuang; Guo, Min] BGI Shenzhen, Shenzhen, Guangdong, Peoples R China.;[Bu, Lijing] Univ New Mexico, Dept Biol, Albuquerque, NM 87131 USA.;[Zhou, Chengran] Sichuan Univ, Dept Biol, Chengdu 610064, Sichuan Provinc, Peoples R China.;[Wang, Yongdong] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang, Hunan, Peoples R China.;[Chen, Liyu] Cent South Univ, Xiangya Sch Med, Dept Microbiol, Changsha, Hunan, Peoples R China.
通讯机构：
[Chen, Liyu] C;Cent South Univ, Xiangya Sch Med, Dept Microbiol, Changsha, Hunan, Peoples R China.
关键词：
Campylobacter;Phylogenetic analysis;Ribosomal RNA;Sequence alignment;Paleogenetics;Multiple alignment calculation;Sequence databases;Viral genomics
摘要：
Campylobacter species.are phenotypically diverse in many aspects including host habitats and pathogenicities, which demands comprehensive characterization of the entire Campylobacter genus to study their underlying genetic diversification. Up to now, 34 Campylobacter strains have been sequenced and published in public databases, providing good opportunity to systemically analyze their genomic diversities. In this study, we first conducted genomic characterization, which includes genome-wide alignments, pan-genome analysis, and phylogenetic identification, to depict the genetic diversity of Campylobacter genus. Afterward, we improved the tetranucleotide usage pattern-based naïve Bayesian classifier to identify the abnormal composition fragments (ACFs, fragments with significantly different tetranucleotide frequency profiles from its genomic tetranucleotide frequency profiles) including horizontal gene transfers (HGTs) to explore the mechanisms for the genetic diversity of this organism. Finally, we analyzed the HGTs transferred via bacteriophage transductions. To our knowledge, this study is the first to use single nucleotide polymorphism information to construct liable microevolution phylogeny of 21 Campylobacter jejuni strains. Combined with the phylogeny of all the collected Campylobacter species based on genome-wide core gene information, comprehensive phylogenetic inference of all 34 Campylobacter organisms was determined. It was found that C. jejuni harbors a high fraction of ACFs possibly through intraspecies recombination, whereas other Campylobacter members possess numerous ACFs possibly via intragenus recombination. Furthermore, some Campylobacter strains have undergone significant ancient viral integration during their evolution process. The improved method is a powerful tool for bacterial genomic analysis. Moreover, the findings would provide useful information for future research on Campylobacter genus.
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英文
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Removal and recovery of uranium (VI) from aqueous solutions by immobilized Aspergillus niger powder beads
作者：
Ding, De-Xin* ;Tan, Xiang;Hu, Nan;Li, Guang-Yue;Wang, Yong-Dong;...
期刊：
Bioprocess and Biosystems Engineering ,2012年35(9):1567-1576 ISSN：1615-7591
通讯作者：
Ding, De-Xin
作者机构：
[Li, Guang-Yue; Tan, Yan; Hu, Nan; Tan, Xiang; Ding, De-Xin; Wang, Yong-Dong] Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.;[Tan, Yan; Ding, De-Xin] Cent S Univ, Sch Resources & Safety Engn, Changsha 410083, Peoples R China.;[Ding, De-Xin] Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, 28 W Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Ding, De-Xin] U;Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, 28 W Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
关键词：
Biosorption;Uranium;Aspergillus niger;Equilibrium;Kinetics
摘要：
The immobilized Aspergillus niger powder beads were obtained by entrapping nonviable A. niger powder into Ca-alginate gel. The effects of pH, contact time, initial uranium (VI) concentration and biomass dosage on the biosorption of uranium (VI) onto the beads from aqueous solutions were investigated in a batch system. Biosorption equilibrium data were agreeable with Langmuir isotherm model and the maximum biosorption capacity of the beads for uranium (VI) was estimated to be 649.4 mg/g at 30 °C. The biosorption kinetics followed the pseudo-second-order model and intraparticle diffusion equation. The variations in enthalpy (26.45 kJ/mol), entropy (0.167 kJ/mol K) and Gibbs free energy were calculated from the experimental data. SEM and EDS analysis indicated that the beads have strong adsorption capability for uranium (VI). The adsorbed uranium (VI) on the beads could be released with HNO3 or HCl. The results showed that the immobilized A. niger powder beads had great potential for removing and recovering uranium (VI) from aqueous solutions. © Springer-Verlag 2012.
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A core-shell structured nanocomposite material for detection, adsorption and removal of Hg(II) ions in water
作者：
Li, Le;Tang, Shuangyang;Ding, Dexin* ;Hu, Nan;Yang, Shengyuan;...
期刊：
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY ,2012年12(11):8407-8414 ISSN：1533-4880
通讯作者：
Ding, Dexin
作者机构：
[Yang, Shengyuan; Tan, Yan; He, Shuya; Li, Le] Univ S China, Sch Publ Hlth, Hengyang 421001, Peoples R China.;[Tang, Shuangyang] Univ S China, Coll Med, Hengyang 421001, Peoples R China.;[Ding, Dexin; Li, Le; Hu, Nan; Sun, Jing; Wang, Yongdong] Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.;[Yang, Shengyuan] Hunan Univ, Coll Chem & Chem Engn, State Key Lab Chemo Biosensing & Chemometr, Changsha 410082, Hunan, Peoples R China.
通讯机构：
[Ding, Dexin] U;Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.
关键词：
Fe_3O_4 Nanoparticles;Pyrene;Detection;Adsorption;Removal;Hg(II)
摘要：
In this paper, a core-shell structured nanocomposite material was prepared for the detection, adsorption and removal of Hg(II) ions in aqueous solution. The core was made from Fe<inf>3</inf>O<inf>4</inf> nanoparticles with superparamagnetic behavior and the outer shell was made from amorphous silica modified with pyrene-based sensing-probes. The material could detect and adsorb Hg(II) ions in aqueous solution due to its surface being modified with pyrene-based sensing-probes, and could easily be removed from the solution by magnetic force because of its core being made from magnetic Fe<inf>3</inf>O <inf>4</inf> nanoparticles. This multifunctional core-shell structure was confirmed and characterized by TEM, IR spectra, TGA, XRD and N<inf>2</inf> adsorption/desorption isotherms. Experiments were conducted on its functions of detection, adsorption and removal of Hg(II) ions in aqueous solution. The experimental results showed that this composite material had high sensitivity and unique selectivity to Hg(II), and that it could easily be removed from the solution. Copyright ©2012 American Scientific Publishers.
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英文
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Screening of plant species for phytoremediation of uranium, thorium, barium, nickel, strontium and lead contaminated soils from a uranium mill tailings repository in South China
作者：
Li, Guang-yue;Hu, Nan;Ding, De-xin* ;Zheng, Ji-fang;Liu, Yu-long;...
期刊：
Bulletin of Environmental Contamination and Toxicology ,2011年86(6):646-652 ISSN：0007-4861
通讯作者：
Ding, De-xin
作者机构：
[Li, Guang-yue; Liu, Yu-long; Nie, Xiao-qin; Hu, Nan; Zheng, Ji-fang; Ding, De-xin; Wang, Yong-dong] Univ S China, Key Discipline Lab Natl Def Biol Technol Uranium, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Ding, De-xin] U;Univ S China, Key Discipline Lab Natl Def Biol Technol Uranium, Hengyang 421001, Hunan, Peoples R China.
关键词：
Uranium;Thorium;Hyperaccumulator;Mill tailings;Phytoremediation factor
摘要：
The concentrations of uranium, thorium, barium, nickel, strontium and lead in the samples of the tailings and plant species collected from a uranium mill tailings repository in South China were analyzed. Then, the removal capability of a plant for a target element was assessed. It was found that Phragmites australis had the greatest removal capabilities for uranium (820 μg), thorium (103 μg) and lead (1,870 μg). Miscanthus floridulus had the greatest removal capabilities for barium (3,730 μg) and nickel (667 μg), and Parthenocissus quinquefolia had the greatest removal capability for strontium (3,920 μg). In this study, a novel coefficient, termed as phytoremediation factor (PF), was proposed, for the first time, to assess the potential of a plant to be used in phytoremediation of a target element contaminated soil. Phragmites australis has the highest PFs for uranium (16.6), thorium (8.68), barium (10.0) and lead (10.5). Miscanthus floridulus has the highest PF for Ni (25.0). Broussonetia papyrifera and Parthenocissus quinquefolia have the relatively high PFs for strontium (28.1 and 25.4, respectively). On the basis of the definition for a hyperaccumulator, only Cyperus iria and Parthenocissus quinquefolia satisfied the criteria for hyperaccumulator of uranium (36.4 μg/g) and strontium (190 μg/g), and could be the candidates for phytoremediation of uranium and strontium contaminated soils. The results show that the PF has advantage over the hyperaccumulator in reflecting the removal capabilities of a plant for a target element, and is more adequate for assessing the potential of a plant to be used in phytoremediation than conventional method. © 2011 Springer Science+Business Media, LLC.
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英文
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Metal pollution in Huayuan river in Hunan province in China by manganese sulphate waste residue
作者：
Hu, Nan;Zheng, Ji-Fang* ;Ding, De-Xin;Liu, Jun;Yang, Lu-Qing;...
期刊：
Bulletin of Environmental Contamination and Toxicology ,2009年83(4):583-590 ISSN：0007-4861
通讯作者：
Zheng, Ji-Fang
作者机构：
[Li, Guang-Yue; Liu, Yu-Long; Yin, Jie; Zheng, Ji-Fang; Yang, Lu-Qing; Hu, Nan; Ding, De-Xin; Liu, Jun; Wang, Yong-Dong] Univ S China, Key Discipline Lab Natl Def Biol Technol Uranium, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Zheng, Ji-Fang] U;Univ S China, Key Discipline Lab Natl Def Biol Technol Uranium, Hengyang 421001, Hunan, Peoples R China.
关键词：
Huayuan River;Manganese sulphate waste residue;Sediment;Speciation;Water pollution
摘要：
The Huayuan River in Hunan Province in China is subject to ongoing mining activity with Mn extraction. In this study, the level and environmental significance of metals (including Mn, Cd, Pb, Cu, Zn, Ni and Fe) concentrations in the surface water and river sediments have been investigated along a 187 km reach of the Huayuan River. Using the X-ray fluorescence (XRF) analysis, we analyzed the characterization of metals in manganese sulphate waste residue (MSWR) deposited along the bank of Huayuan River. The speciation of metals in both sediment and MSWR was established using the BCR-three step sequential extraction procedure. In the water samples, the average concentrations of Mn, Cd and Pb exceeded the acceptable concentrations for drinking water in the WHO Guidelines for drinking water quality, Vol. 1, Recommendations, Geneva (2004) and Chinese (GB 5749-2006) guidelines, respectively. The average concentrations of Mn, Cd, Pb and Zn in the river sediments were found to be considerably higher than the corresponding world average shale values. The percentages of Cd (31.4%), Mn (31.1%), Zn (12.8%) and Pb (8.1%) associated with exchangeable and weak acid fraction in the sediments were higher than other metals. Mn (5.81%), Zn (0.208%), Pb (0.0292%) and Cd (0.0113%) were identified in MSWR by XRF analysis. The percentages of Mn, Cd, Zn and Pb associated with the exchangeable and weak acid soluble fraction in MSWR were 41.9%, 31.1%, 23.8% and 9.8%, respectively. The peak solute and sediment-bound metal concentrations were found at the sites of MSWR deposited along the bank of Huayuan River. The results suggested that MSWR deposited along the bank may have a closely relation with the metal pollution of Huayuan River. The results obtained may be useful to assess both short and long-term environmental impact of the MSWR deposited activities and support decisions for a future remediation of this river. © 2009 Springer Science+Business Media, LLC.
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英文
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