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Polycyclic aromatic hydrocarbons (PAHs) are considered as an external factor that induces atherosclerotic cardiovascular disease. Although miR-155 is known to be involved in cardiovascular disease, whether it is involved in PAH-induced arteriosclerosis remains unclear. We evaluated the effects of PAHs on vascularization, permeability, and miR-155 expression in HUVECs. We found that PAHs-induced sclerosis of HUVECs was characterized by increasing permeability, decreasing proliferation, and vascular lumen number. The expression of miR-155 was upregulated by PAHs treatment, and transfection with miR-155 inhibitor could reverse above effect of PAHs-induced sclerosis. Meanwhile, transcriptome sequencing revealed that 63 genes were downregulated in the group of PAHs treatment alone, and were then upregulated in the miR-155 inhibitor group. These genes were mainly involved in complement and coagulation cascades, cytokine-cytokine receptor interaction, TNF signaling pathway, and NF-kappa B signaling pathway. Among these 63 genes, SERPIND1 was directly targeted and regulated by miR-155. Further in vivo experiments in ApoE−/−mice confirmed that PAH accelerates the development of arteriosclerosis by promoting the expression of miR-155 to downregulate the SERPIND1. Therefore, PAH exaggerates atherosclerosis by activating miR-155-dependent endothelial injury. This study provides a fundamental insight on the miR-155 mechanism for PAHs enhancing atherosclerosis and miR-155 potentially serving as a novel drug target.
Xiao‐Nan He; Jin‐Yuan Xin; Jin‐Liang Zhan; Fang‐Kun Wu; Jian Hou; Zhao‐Bin Sun; Ji Wang; Xiao‐Ling Zhang; Ying‐Chen Bai. Polycyclic aromatic hydrocarbons induce endothelial injury through miR‐155 to promote atherosclerosis. Environmental and Molecular Mutagenesis 2021, 62, 409 -421.
AMA StyleXiao‐Nan He, Jin‐Yuan Xin, Jin‐Liang Zhan, Fang‐Kun Wu, Jian Hou, Zhao‐Bin Sun, Ji Wang, Xiao‐Ling Zhang, Ying‐Chen Bai. Polycyclic aromatic hydrocarbons induce endothelial injury through miR‐155 to promote atherosclerosis. Environmental and Molecular Mutagenesis. 2021; 62 (7):409-421.
Chicago/Turabian StyleXiao‐Nan He; Jin‐Yuan Xin; Jin‐Liang Zhan; Fang‐Kun Wu; Jian Hou; Zhao‐Bin Sun; Ji Wang; Xiao‐Ling Zhang; Ying‐Chen Bai. 2021. "Polycyclic aromatic hydrocarbons induce endothelial injury through miR‐155 to promote atherosclerosis." Environmental and Molecular Mutagenesis 62, no. 7: 409-421.
Surface activity of humic acid (HA) and its six sub-fractions isolated from forest soil were characterized by surface tension measurements, dynamic light scattering, and laser doppler electrophoresis. The surface tension of HA and its sub-fractions reduced from 72.4 mN·m−1 to 36.8 mN·m−1 in exponential model with the increasing concentration from 0 to 2000 mg·L−1. The critical micelle concentration (CMC) and Z-average particle size ranged from 216–1024 mg·L−1 and 108.2–186.9 nm for HA and its sub-fractions, respectively. The CMC have related with alkyl C, O-alkyl C, aromatic C, and carbonyl C (p< 0.05), respectively, and could be predicted with the multiple linear regression equation of CMC, CMC = 18896 − 6.9 × C-296 × alkyl C-331 × aromatic C-17019 × H/C + 4054 × HB/HI (p< 0.05). The maximum particle size was 5000 nm after filtered by a membrane with pore size of 450 nm, indicating HA and its sub-fractions could progressed self-assembly at pH 6.86. The aggregate sizes of number-base particle size distributions were mainly in six clusters including 2 ± 1 nm, 5 ± 2 nm, 10 ± 3 nm, 21 ± 8 nm, 40 ± 10 nm, and >50 nm analyzed by Gaussian model that maybe due to the inconsistency of the components and structures of the HA sub-fractions, requiring further study. It is significance to explore the surface activity of HA and its sub-fractions, which is helpful to clarify the environmental behavior of HA.
Shijie Tian; Weiqiang Tan; Xinyuan Wang; Tingting Li; Fanhao Song; Nannan Huang; Yingchen Bai. Surface Activity of Humic Acid and Its Sub-Fractions from Forest Soil. Sustainability 2021, 13, 8122 .
AMA StyleShijie Tian, Weiqiang Tan, Xinyuan Wang, Tingting Li, Fanhao Song, Nannan Huang, Yingchen Bai. Surface Activity of Humic Acid and Its Sub-Fractions from Forest Soil. Sustainability. 2021; 13 (15):8122.
Chicago/Turabian StyleShijie Tian; Weiqiang Tan; Xinyuan Wang; Tingting Li; Fanhao Song; Nannan Huang; Yingchen Bai. 2021. "Surface Activity of Humic Acid and Its Sub-Fractions from Forest Soil." Sustainability 13, no. 15: 8122.
Fanhao Song; Tingting Li; Quan Shi; Fei Guo; Yingchen Bai; Fengchang Wu; Baoshan Xing. Novel Insights into the Molecular-Level Mechanism Linking the Chemical Diversity and Copper Binding Heterogeneity of Biochar-Derived Dissolved Black Carbon and Dissolved Organic Matter. Environmental Science & Technology 2021, 1 .
AMA StyleFanhao Song, Tingting Li, Quan Shi, Fei Guo, Yingchen Bai, Fengchang Wu, Baoshan Xing. Novel Insights into the Molecular-Level Mechanism Linking the Chemical Diversity and Copper Binding Heterogeneity of Biochar-Derived Dissolved Black Carbon and Dissolved Organic Matter. Environmental Science & Technology. 2021; ():1.
Chicago/Turabian StyleFanhao Song; Tingting Li; Quan Shi; Fei Guo; Yingchen Bai; Fengchang Wu; Baoshan Xing. 2021. "Novel Insights into the Molecular-Level Mechanism Linking the Chemical Diversity and Copper Binding Heterogeneity of Biochar-Derived Dissolved Black Carbon and Dissolved Organic Matter." Environmental Science & Technology , no. : 1.
Pyrolysis is a promising treatment for soil remediation for rapidity and fertility preservation. But it is difficult to establish the relationship between pyrolysis behaviors and soil organic matter (SOM) structures, for SOM is a mixture of heterogeneous compounds. HA sub-fractions from the same soil source may provide a series of promising objects to understand SOM at molecular level and the resulting patterns in SOM pyrolysis. We first propose a novel insight into pyrolysis mechanism response to molecular signatures using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) combined with thermogravimetric analysis (TGA) to study six humic acid (HA) sub-fractions extracted from a forest soil. The findings indicate that decomposition of soil HA occurs systematically due to molecular signatures. The decomposition can be categorized as carboxyl controlled (below 280 °C), lipid-dominated (280–450 °C) and condensed aromatics-dominated processes (450–700 °C). Predominant reaction mechanism of all HA sub-fractions was random nucleation (α > 0.25). Lipid in HA tend to initiate multiple nuclei in thermal degradation, while condensed aromatics tend to initiate and grow centering single random point in higher conversion rate (α > 0.75). Bridging the molecular signature and thermogravimetry reveals that the pyrolysis stage below 350 °C should be divided into two distinct processes related to the carboxylic group and lipid compounds, although this stage has conventionally been considered as a single process. The N element of HA was mostly preserved in the condensed aromatics which was mainly pyrolyzed above 450 °C, suggesting that pyrolysis below 450 °C is a preferable remediation treatment considering nitrogen fertility preservation. The observed molecular-level pyrolysis patterns can be applied as a targeted remediation procedure for contaminated soils and can improve the understanding of SOM thermal behaviors at the molecular level.
Fei Guo; Shuai Qin; Lei Xu; Yingchen Bai; Baoshan Xing. Thermal degradation features of soil humic acid sub-fractions in pyrolytic treatment and their relation to molecular signatures. Science of The Total Environment 2020, 749, 142318 .
AMA StyleFei Guo, Shuai Qin, Lei Xu, Yingchen Bai, Baoshan Xing. Thermal degradation features of soil humic acid sub-fractions in pyrolytic treatment and their relation to molecular signatures. Science of The Total Environment. 2020; 749 ():142318.
Chicago/Turabian StyleFei Guo; Shuai Qin; Lei Xu; Yingchen Bai; Baoshan Xing. 2020. "Thermal degradation features of soil humic acid sub-fractions in pyrolytic treatment and their relation to molecular signatures." Science of The Total Environment 749, no. : 142318.
Nonylphenol is a typical endocrine-disrupting chemical that has received considerable attention from government officials, scientists and the public due to its estrogenicity and ubiquitous occurrence in water environments. Here we review the current knowledge on nonylphenol occurrence, distribution, toxic effects and water quality criteria related to the protection of freshwater organisms. Nonylphenol enters the water ecosystem mainly via wastewater treatment plant effluents, agricultural runoff, groundwater discharge from air, soil, water and agricultural sources. Toxic effects of nonylphenol on aquatic organisms include acute toxic effects, growth and development effects, estrogenic effect and reproductive effects, neurotoxicity, liver toxicity and immunotoxicity.
Yajun Hong; Chenglian Feng; Zhenfei Yan; Ying Wang; Daqing Liu; Wei Liao; Yingchen Bai. Nonylphenol occurrence, distribution, toxicity and analytical methods in freshwater. Environmental Chemistry Letters 2020, 18, 2095 -2106.
AMA StyleYajun Hong, Chenglian Feng, Zhenfei Yan, Ying Wang, Daqing Liu, Wei Liao, Yingchen Bai. Nonylphenol occurrence, distribution, toxicity and analytical methods in freshwater. Environmental Chemistry Letters. 2020; 18 (6):2095-2106.
Chicago/Turabian StyleYajun Hong; Chenglian Feng; Zhenfei Yan; Ying Wang; Daqing Liu; Wei Liao; Yingchen Bai. 2020. "Nonylphenol occurrence, distribution, toxicity and analytical methods in freshwater." Environmental Chemistry Letters 18, no. 6: 2095-2106.
The characteristics of subfractions of soil fulvic acid (FA3, FA5, FA7, FA9, and FA13) using stepwise elution from XAD-8 resin with pyrophosphate buffers were investigated by differential absorption spectroscopy (DAS) and differential fluorescence spectroscopy (DFS) combined with mathematical deconvolution and spectral indices. The log-transformed absorbance spectra (LTAS) exhibited three regions for both acidic-buffer-eluted subfractions (AESF) and neutral-buffer-eluted subfraction (NESF) and four regions for basic-buffer-eluted subfractions (BESF) according to the differences in spectral slopes. The DAS spectra of FA subfractions were closely fitted with seven Gaussian bands with maxima location at 199.66, 216.18 ± 1.50, 246.20 ± 3.85, 285.22 ± 7.26, 345.64 ± 5.30, 389.27, and 307.37 nm, respectively (R2 > 0.993). The content of salicylic-like and carboxyl groups in FA subfractions decreased, while the phenolic chromophore increased with elution sequence. From the 11 spectral indices, AESF had greater molecular weight, condensation, polymerization, hydroxyl radical production, humification degree, and terrigenous contribution, as well as contained more conjugated aromatic structures and less N-containing groups than NESF and BESF. The humification degree and humic characters of FA subfractions were closely associated to the aromaticity, molecular condensation, and DOM–metal-bound functional groups. The proper separation of FA into subfractions is beneficial for reducing its complexity and heterogeneity, which helps us to further explore its chemical properties and interactions with various contaminants in soil environments.
Tingting Li; Fanhao Song; Jin Zhang; Shasha Liu; Weiying Feng; Lingling Zuo; Jia Pu; Baoshan Xing; John P. Giesy; Yingchen Bai. Investigation of eluted characteristics of fulvic acids using differential spectroscopy combined with Gaussian deconvolution and spectral indices. Environmental Science and Pollution Research 2020, 27, 11000 -11011.
AMA StyleTingting Li, Fanhao Song, Jin Zhang, Shasha Liu, Weiying Feng, Lingling Zuo, Jia Pu, Baoshan Xing, John P. Giesy, Yingchen Bai. Investigation of eluted characteristics of fulvic acids using differential spectroscopy combined with Gaussian deconvolution and spectral indices. Environmental Science and Pollution Research. 2020; 27 (10):11000-11011.
Chicago/Turabian StyleTingting Li; Fanhao Song; Jin Zhang; Shasha Liu; Weiying Feng; Lingling Zuo; Jia Pu; Baoshan Xing; John P. Giesy; Yingchen Bai. 2020. "Investigation of eluted characteristics of fulvic acids using differential spectroscopy combined with Gaussian deconvolution and spectral indices." Environmental Science and Pollution Research 27, no. 10: 11000-11011.
Simulated photo-degradation of fluorescent dissolved organic matter (FDOM) in Lake Baihua (BH) and Lake Hongfeng (HF) was investigated with three-dimensional excitation-emission matrix (3DEEM) fluorescence combined with the fluorescence regional integration (FRI), parallel factor (PARAFAC) analysis, and multi-order kinetic models. In the FRI analysis, fulvic-like and humic-like materials were the main constituents for both BH-FDOM and HF-FDOM. Four individual components were identified by use of PARAFAC analysis as humic-like components (C1), fulvic-like components (C2), protein-like components (C3) and unidentified components (C4). The maximum 3DEEM fluorescence intensity of PARAFAC components C1–C3 decreased by about 60%, 70% and 90%, respectively after photo-degradation. The multi-order kinetic model was acceptable to represent the photo-degradation of FDOM with correlation coefficient (Radj2) (0.963–0.998). The photo-degradation rate constants (kn) showed differences of three orders of magnitude, from 1.09 × 10−6 to 4.02 × 10−4 min−1, and half-life of multi-order model ( T1/2n) ranged from 5.26 to 64.01 min. The decreased values of fluorescence index (FI) and biogenic index (BI), the fact that of percent fluorescence response parameter of Region I (PI,n) showed the greatest change ratio, followed by percent fluorescence response parameter of Region II (PII,n), while the largest decrease ratio was found for C3 components, and the lowest T1/2n was observed for C3, indicated preferential degradation of protein-like materials/components derived from biological sources during photo-degradation. This research on the degradation of FDOM by 3DEEM/FRI-PARAFAC would be beneficial to understanding the photo-degradation of FDOM in natural environments and accurately predicting the environmental behaviors of contaminants in the presence of FDOM.
Jin Zhang; Fanhao Song; Tingting Li; Kefu Xie; Huiying Yao; Baoshan Xing; Zhongyu Li; Yingchen Bai. Simulated photo-degradation of dissolved organic matter in lakes revealed by three-dimensional excitation-emission matrix with regional integration and parallel factor analysis. Journal of Environmental Sciences 2019, 90, 310 -320.
AMA StyleJin Zhang, Fanhao Song, Tingting Li, Kefu Xie, Huiying Yao, Baoshan Xing, Zhongyu Li, Yingchen Bai. Simulated photo-degradation of dissolved organic matter in lakes revealed by three-dimensional excitation-emission matrix with regional integration and parallel factor analysis. Journal of Environmental Sciences. 2019; 90 ():310-320.
Chicago/Turabian StyleJin Zhang; Fanhao Song; Tingting Li; Kefu Xie; Huiying Yao; Baoshan Xing; Zhongyu Li; Yingchen Bai. 2019. "Simulated photo-degradation of dissolved organic matter in lakes revealed by three-dimensional excitation-emission matrix with regional integration and parallel factor analysis." Journal of Environmental Sciences 90, no. : 310-320.
Biomass, a renewable energy source, via available thermo-chemical processes has both engineering and environmental advantages. However, the understanding of the kinetics, evolved gases and mechanisms for biomass pyrolysis is limited. We first propose a novel temperature response mechanism for the pyrolysis of sugar cane residue using thermogravimetric analysis-Fourier transform infrared spectrometry-mass spectrometry (TG-FTIR-MS) combined with Gaussian model and two-dimensional correlation spectroscopy (2D COS). The existence and contribution of distinct peaks in TG-FTIR spectra were innovatively distinguished and quantified, and the temperature-dependent dynamics of gas amounts were determined using Gaussian deconvolution. The 2D-TG-FTIR/MS-COS results revealed for the first time that the primary sequential temperature responses of gases occurred in the order: H2O/CH4 > phenols/alkanes/aromatics/alcohols > carboxylic acids/ketones > CO2/ethers > aldehyde groups/acetaldehyde. Subtle sequential changes even occurred within the same gases during pyrolysis. The quantity dynamics and sequential responses of gases were fitted to the combined effects of the order-based, diffusion and chemical reaction mechanisms for the component degradation. The combination of TG-FTIR-MS, Gaussian model and 2D COS is a promising approach for the online monitoring and real-time management of biomass pyrolysis, providing favorable strategies for pyrolysis optimization, by-product recovery, energy generation and gas emission control in engineering and environmental applications.
Fanhao Song; Tingting Li; Jin Zhang; Xiaojie Wang; Yingchen Bai; John P. Giesy; Baoshan Xing; Fengchang Wu. Novel Insights into the Kinetics, Evolved Gases, and Mechanisms for Biomass (Sugar Cane Residue) Pyrolysis. Environmental Science & Technology 2019, 53, 13495 -13505.
AMA StyleFanhao Song, Tingting Li, Jin Zhang, Xiaojie Wang, Yingchen Bai, John P. Giesy, Baoshan Xing, Fengchang Wu. Novel Insights into the Kinetics, Evolved Gases, and Mechanisms for Biomass (Sugar Cane Residue) Pyrolysis. Environmental Science & Technology. 2019; 53 (22):13495-13505.
Chicago/Turabian StyleFanhao Song; Tingting Li; Jin Zhang; Xiaojie Wang; Yingchen Bai; John P. Giesy; Baoshan Xing; Fengchang Wu. 2019. "Novel Insights into the Kinetics, Evolved Gases, and Mechanisms for Biomass (Sugar Cane Residue) Pyrolysis." Environmental Science & Technology 53, no. 22: 13495-13505.
Water quality criteria are the basis for formulating environmental water quality standards, and are also an important part of environmental water protection and environmental management programs. The current study focused on a systematic discussion of the current research progress of water quality criteria theories and methodology for aquatic organisms both in China and internationally. This study also successfully pointed out key scientific issues which should be considered in the determination of water quality criteria guidelines from the following perspectives for a national strategy: the selection of pollutants; data collection and screening; species selection; water quality criteria derivation methods, and so on. For the first time, this study systematically introduced technology for the determination of water quality criteria guidelines for protecting aquatic organisms which was suitable for China's regional characteristics and national conditions. Furthermore, this study pointed out the key research directions which should be considered in the future construction of China's environmental criteria and management systems, in order to provide technical support for environmental protection and management projects.
Chenglian Feng; Hui Li; Zhenfei Yan; Yujuan Wang; Chen Wang; Zhiyou Fu; Wei Liao; John P. Giesy; Yingchen Bai. Technical study on national mandatory guideline for deriving water quality criteria for the protection of freshwater aquatic organisms in China. Journal of Environmental Management 2019, 250, 109539 .
AMA StyleChenglian Feng, Hui Li, Zhenfei Yan, Yujuan Wang, Chen Wang, Zhiyou Fu, Wei Liao, John P. Giesy, Yingchen Bai. Technical study on national mandatory guideline for deriving water quality criteria for the protection of freshwater aquatic organisms in China. Journal of Environmental Management. 2019; 250 ():109539.
Chicago/Turabian StyleChenglian Feng; Hui Li; Zhenfei Yan; Yujuan Wang; Chen Wang; Zhiyou Fu; Wei Liao; John P. Giesy; Yingchen Bai. 2019. "Technical study on national mandatory guideline for deriving water quality criteria for the protection of freshwater aquatic organisms in China." Journal of Environmental Management 250, no. : 109539.
The incorporation and cycling of pyrogenic organic matter in soil is a potential carbon sink, while the pyrolysis behaviors of soil organic matter are still lacking. Pyrolysis characteristics of soil fulvic acid (FA) and humic acid (HA) were investigated using thermogravimetry combined with Fourier transform infrared spectrometer-mass spectrometer (TG-FTIR-MS) and kinetic models. Four reaction stages corresponding to four pseudo-components were distinguished for both FA and HA. FA exhibited greater transformation contributions of hemicellulose-like and cellulose-like pseudo-components, while HA exhibited greater transformation contributions of lignin-like pseudo-components. Compared to HA, higher levels of heat-resistant aromatic compounds, phenolic groups, and carboxylic groups were recognized in FA. Values of both activation energy (Ea, 246.13–661.40 kJ·mol−1) and pre-exponential factor (lnA, 53.49–107.16 min−1) of FA were greater than corresponding Ea (241.74–466.70 kJ·mol−1) and lnA (51.99–74.36 min−1) values of HA determined by Flynn-Wall-Ozawa method and Distributed Activation Energy Model. The main pyrolysis reaction mechanisms of both FA and HA closely matched with the order-based model corresponding to 2nd and 3rd order random nucleation on an individual particle. The evolved gas species of H2, CH4, H2O, and CO2 were dominant for FA and HA pyrolysis. Generally, the total H2/CO2 and CH4/H2O releases were relatively larger for FA and HA pyrolysis, respectively. TG-FTIR-MS is shown to be an effective method to provide valuable and qualitative analysis of the gaseous volatile species evolved during HS pyrolysis. Findings from this systematic study of soil organic matter responding to pyrolysis will be critical for predicting the changes of soil systems or carbon cycle affected by future climate and fire regimes.
Tingting Li; Fanhao Song; Jin Zhang; Shasha Liu; Baoshan Xing; Yingchen Bai. Pyrolysis characteristics of soil humic substances using TG-FTIR-MS combined with kinetic models. Science of The Total Environment 2019, 698, 134237 .
AMA StyleTingting Li, Fanhao Song, Jin Zhang, Shasha Liu, Baoshan Xing, Yingchen Bai. Pyrolysis characteristics of soil humic substances using TG-FTIR-MS combined with kinetic models. Science of The Total Environment. 2019; 698 ():134237.
Chicago/Turabian StyleTingting Li; Fanhao Song; Jin Zhang; Shasha Liu; Baoshan Xing; Yingchen Bai. 2019. "Pyrolysis characteristics of soil humic substances using TG-FTIR-MS combined with kinetic models." Science of The Total Environment 698, no. : 134237.
When tailing spill accidents occur, the risk of contamination by antimony (Sb) tailings into adjacent rivers, sediments, aquifers and soil environments is high. The Sb concentrations in water and sediment under different stringent control activities were investigated for 60 days in the Jialing River basin after a tailing spill accident. Both reservoir regulation and the construction of a temporary dam with coagulation dosing remarkably reduced the Sb levels in the river water. The increase in dissolved Sb caused by the spill was reduced from ~400 μg/L in the inflow to ~200 μg/L in the outflow by reservoir regulation. Moreover, reservoir regulation led to a high concentration of Sb in the reservoir sediment, which was difficult to remove and may cause subsequent unpredictable long-term ecological and health risks. In contrast, the Sb-enriched deposition inside the temporary dam was convenient to remove. Notably, temperature alternations between day and night in winter resulted in a large fluctuation in coagulation efficiency, which may cause the failure of stringent control projects. The results of this study suggest potential improvements to stringent control activities after mine tailing accidents to mitigate environmental impacts and prevent secondary risks.
F. Guo; F.C. Wu; F. Yu; Y.C. Bai; Z.Y. Fu; Y.R. Zhu; W.J. Guo. Fate and removal of antimony in response to stringent control activities after a mine tailing spill. Science of The Total Environment 2019, 693, 133604 .
AMA StyleF. Guo, F.C. Wu, F. Yu, Y.C. Bai, Z.Y. Fu, Y.R. Zhu, W.J. Guo. Fate and removal of antimony in response to stringent control activities after a mine tailing spill. Science of The Total Environment. 2019; 693 ():133604.
Chicago/Turabian StyleF. Guo; F.C. Wu; F. Yu; Y.C. Bai; Z.Y. Fu; Y.R. Zhu; W.J. Guo. 2019. "Fate and removal of antimony in response to stringent control activities after a mine tailing spill." Science of The Total Environment 693, no. : 133604.
In aquatic systems, dissolved organic matter (DOM) plays an important role in regulating the reactivity and transport of environmental pollutants. Fluorescence excitation-emission matrix (EEM) analysis combined with fluorescence regional integration (FRI) and parallel factorial analysis (PARAFAC) were applied to investigate the composition, humification degree and depth-dependent variation of DOM in Lake Baihua, China. The results showed that humic-like materials with more than 60% of percentage fluorescence response (Pi,n) were dominant in DOM. The molecular complexity and structural condensation of PARAFAC components showed the order of C1 (humic-like components) > C3 (protein-like components) > C4 (fulvic-like components) > C2 (fulvic-like components). The lower maximum fluorescence intensities (Fmax) of components in surface layers were attributed to photo-oxidation of DOM by radiation. With depths less than 16 m, the Fmax increases and decreases were attributed to accumulation of recalcitrant humic substances and microbial/abiotic degradation of particulate DOM, respectively. A combination of biological and humification indices could be used as indicators for distinguishing different degrees of humification and sources of DOM. DOM from Lake Baihua mainly originated from an aquatic bacterial source that consisted of an important/intermediate autochthonous component with a weak humic character. The fluorescence indices of PI,n/PII,n, PI+II+IV,n/PIII+V,n, C2, C1/C2 and C2/(C3+C4) were more suitable to determine the humification degree. Stronger humic characters and higher humification degree for DOM were present at depths of 10–13 m. The fluorescence spectroscopy combined with fluorescence indices is convenient to investigate depth-dependent DOM characteristics and to assess water quality or pollution risk in lake systems.
Fanhao Song; Fengchang Wu; Weiying Feng; Shasha Liu; Jia He; Tingting Li; Jin Zhang; Aiming Wu; Dulasiri Amarasiriwardena; Baoshan Xing; Yingchen Bai. Depth-dependent variations of dissolved organic matter composition and humification in a plateau lake using fluorescence spectroscopy. Chemosphere 2019, 225, 507 -516.
AMA StyleFanhao Song, Fengchang Wu, Weiying Feng, Shasha Liu, Jia He, Tingting Li, Jin Zhang, Aiming Wu, Dulasiri Amarasiriwardena, Baoshan Xing, Yingchen Bai. Depth-dependent variations of dissolved organic matter composition and humification in a plateau lake using fluorescence spectroscopy. Chemosphere. 2019; 225 ():507-516.
Chicago/Turabian StyleFanhao Song; Fengchang Wu; Weiying Feng; Shasha Liu; Jia He; Tingting Li; Jin Zhang; Aiming Wu; Dulasiri Amarasiriwardena; Baoshan Xing; Yingchen Bai. 2019. "Depth-dependent variations of dissolved organic matter composition and humification in a plateau lake using fluorescence spectroscopy." Chemosphere 225, no. : 507-516.
Structural characteristics and proton binding properties of sub-fractions (FA3–FA13) of fulvic acid (FA), eluted stepwise by pyrophosphate buffer were examined by use of fluorescence titration combined with fluorescence regional integration (FRI) and differential fluorescence spectroscopy (DFS). Humic-like (H-L) and fulvic-like (F-L) materials, which accounted for more than 80% of fluorescence response, were dominant in five sub-fractions of FA. Based on FRI analysis, except the response of F-L materials in FA9 and FA13, maximum changes in percent fluorescence response were less than 10% as pH was increased from 2.5 to 11.5. Contents of carboxylic and phenolic groups were compared for fluorescence peaks of FA sub-fractions based on pH-dependent fluorescence derived from DFS. Static quenching was the dominant mechanism for binding of protons by FA sub-fractions. Dissociation constants (pKa) were calculated by use of results of DFS and the modified Stern-Volmer relationship. The pKa of H-L, F-L, tryptophan-like and tyrosine-like materials of FA sub-fractions exhibited ranges of 3.17–4.06, 3.12–3.97, 4.14–4.45 and 4.25–4.76, respectively, for acidic pHs. At basic pHs, values of pKa for corresponding materials were in ranges of 9.71–10.24, 9.62–10.99, 9.67–10.31 and 9.33–10.28, respectively. At acidic pH, protein-like (P-L) materials had greater affinities for protons than did either H-L or F-L materials. The di-carboxylic and phenolic groups were likely predominant sites of protonation for both H-L and F-L materials at both acidic and basic pHs. Amino acid groups were significant factors during proton binding to protein-like materials of FA sub-fractions at basic pH.
Fanhao Song; Fengchang Wu; Weiying Feng; Zhi Tang; John P. Giesy; Fei Guo; Di Shi; Xiaofei Liu; Ning Qin; Baoshan Xing; Yingchen Bai. Fluorescence regional integration and differential fluorescence spectroscopy for analysis of structural characteristics and proton binding properties of fulvic acid sub-fractions. Journal of Environmental Sciences 2018, 74, 116 -125.
AMA StyleFanhao Song, Fengchang Wu, Weiying Feng, Zhi Tang, John P. Giesy, Fei Guo, Di Shi, Xiaofei Liu, Ning Qin, Baoshan Xing, Yingchen Bai. Fluorescence regional integration and differential fluorescence spectroscopy for analysis of structural characteristics and proton binding properties of fulvic acid sub-fractions. Journal of Environmental Sciences. 2018; 74 ():116-125.
Chicago/Turabian StyleFanhao Song; Fengchang Wu; Weiying Feng; Zhi Tang; John P. Giesy; Fei Guo; Di Shi; Xiaofei Liu; Ning Qin; Baoshan Xing; Yingchen Bai. 2018. "Fluorescence regional integration and differential fluorescence spectroscopy for analysis of structural characteristics and proton binding properties of fulvic acid sub-fractions." Journal of Environmental Sciences 74, no. : 116-125.
Heterogeneous distributions of proton binding sites within sub-fractions of fulvic acid (FA3-FA13) were investigated by use of synchronous fluorescence spectra (SFS), combined with principle component analysis (PCA) and two-dimensional correlation spectroscopy (2D-COS). Tryptophan-like, fulvic-like and humic-like materials were observed in SFS. Tyrosine-like materials were identified by use of SFS-PCA analysis. Combined information from synchronous-asynchronous maps and dissociation constants (pKa) was used to describe heterogeneity of binding sites for protons within each sub-fraction. Heterogeneous distributions of proton binding sites were observed in fulvic-like, humic-like, tryptophan-like, and tyrosine-like materials of five sub-fractions and even in the single fulvic-like materials in FA3 and tryptophan-like materials in FA9 and FA13. Values of pKa of sub-fractions ranged from 2.20 to 5.29, depending on associated wavelengths in synchronous-asynchronous maps and use of the modified Stern-Volmer equation. The larger values of pKa (4.17-5.29) were established for protein-like materials (including tryptophan-like and tyrosine-like materials) in comparison to those (2.20-3.38) for humic-like and fulvic-like materials in sub-fractions. Sequential variations of 274nm (pKa 4.15-5.29)→360-460nm (pKa 2.78-2.39) for FA5-FA13 revealed that binding of protons to tryptophan-like materials appeared prior to humic-like/fulvic-like materials. In FA9, protons were preferentially binding to tryptophan-like materials than tyrosine-like materials. In FA3, protons were preferentially binding to humic-like materials than fulvic-like materials. Relative differences of values of pKa for fluorescent materials within each sub-fraction were consistent with sequential orders derived from asynchronous maps. Such an integrated approach, SFS-PCA/2D-COS, has superior potential for further applications in exploring complex interactions between dissolved organic matter and contaminants in engineered and natural environments.
Fanhao Song; Fengchang Wu; Baoshan Xing; Tingting Li; Weiying Feng; John P. Giesy; Wenjing Guo; Hao Wang; Shasha Liu; Yingchen Bai. Protonation-dependent heterogeneity in fluorescent binding sites in sub-fractions of fulvic acid using principle component analysis and two-dimensional correlation spectroscopy. Science of The Total Environment 2018, 616-617, 1279 -1287.
AMA StyleFanhao Song, Fengchang Wu, Baoshan Xing, Tingting Li, Weiying Feng, John P. Giesy, Wenjing Guo, Hao Wang, Shasha Liu, Yingchen Bai. Protonation-dependent heterogeneity in fluorescent binding sites in sub-fractions of fulvic acid using principle component analysis and two-dimensional correlation spectroscopy. Science of The Total Environment. 2018; 616-617 ():1279-1287.
Chicago/Turabian StyleFanhao Song; Fengchang Wu; Baoshan Xing; Tingting Li; Weiying Feng; John P. Giesy; Wenjing Guo; Hao Wang; Shasha Liu; Yingchen Bai. 2018. "Protonation-dependent heterogeneity in fluorescent binding sites in sub-fractions of fulvic acid using principle component analysis and two-dimensional correlation spectroscopy." Science of The Total Environment 616-617, no. : 1279-1287.
In aquatic environments, pH can control environmental behaviors of fulvic acid (FA) via regulating hydrolysis of functional groups. Sub-fractions of FA, eluted using pyrophosphate buffers with initial pHs of 3.0 (FA3), 5.0 (FA5), 7.0 (FA7), 9.0 (FA9) and 13.0 (FA13), were used to explore interactions between the various, operationally defined, FA fractions and protons, by use of EEM-PARAFAC analysis. Splitting of peaks (FA3 and FA13), merging of peaks (FA7), disappearance of peaks (FA9 and FA13), and red/blue-shifting of peaks were observed during fluorescence titration. Fulvic-like components were identified from FA3-FA13, and protein-like components were observed in fractions FA9 and FA13. There primary compounds (carboxylic-like, phenolic-like, and protein-like chromophores) in PARAFAC components were distinguished based on acid-base properties. Dissociation constants (pKa) for fulvic-like components with proton ranged from 2.43 to 4.13 in an acidic pH and from 9.95 to 11.27 at basic pH. These results might be due to protonation of di-carboxylate and phenolic functional groups. At basic pH, pKa values of protein-like components (9.77-10.13) were similar to those of amino acids. However, at acidic pH, pKa values of protein-like components, which ranged from 3.33 to 4.22, were 1-2units greater than those of amino acids. Results presented here, will benefit understanding of environmental behaviors of FA, as well as interactions of FA with environmental contaminants.
Fanhao Song; Fengchang Wu; Fei Guo; Hao Wang; Weiying Feng; Min Zhou; Yanghui Deng; Yingchen Bai; Baoshan Xing; John P. Giesy. Interactions between stepwise-eluted sub-fractions of fulvic acids and protons revealed by fluorescence titration combined with EEM-PARAFAC. Science of The Total Environment 2017, 605-606, 58 -65.
AMA StyleFanhao Song, Fengchang Wu, Fei Guo, Hao Wang, Weiying Feng, Min Zhou, Yanghui Deng, Yingchen Bai, Baoshan Xing, John P. Giesy. Interactions between stepwise-eluted sub-fractions of fulvic acids and protons revealed by fluorescence titration combined with EEM-PARAFAC. Science of The Total Environment. 2017; 605-606 ():58-65.
Chicago/Turabian StyleFanhao Song; Fengchang Wu; Fei Guo; Hao Wang; Weiying Feng; Min Zhou; Yanghui Deng; Yingchen Bai; Baoshan Xing; John P. Giesy. 2017. "Interactions between stepwise-eluted sub-fractions of fulvic acids and protons revealed by fluorescence titration combined with EEM-PARAFAC." Science of The Total Environment 605-606, no. : 58-65.