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Li P.-H.,Shandong University | Li P.-H.,Tianjin University of Technology | Wang Y.,Shandong University | Li Y.-H.,Shandong University | And 4 more authors.
Atmospheric Environment | Year: 2016

Multi-phase (gaseous, particulate and rain) samples were collected simultaneously for the first time at a high-elevation mountain site in China during March to May 2009. The site, located in the free troposphere, is used to investigate the gas-particle partitioning, precipitation scavenging of polycyclic aromatic hydrocarbons (PAHs). The total measured concentrations of 15 USEPA PAHs varied from 2.67 to 137.00 ng/m3 (average of 24.10 ng/m3). Partitioning of PAHs between gaseous and particulate phases (log Kp) was well-correlated with the supercooled liquid vapor pressure in all samples (R2 = 0.730-0.985), but the slopes (-0.154 to -0.424) were significantly deviated from the expected value of -1. The observed Kp values were better predicted by the Dual model than the Koa model, pointing to the importance of soot carbon for PAH partitioning. The scavenging ratios varied among the individual PAH compound, ranged from 4.47 × 103 (BaA) to 1.02 × 105 (ACY). Particle scavenging was the dominant removal process, accounting over 75% of the total scavenging (except for BbF) for individual PAH compound. Relationships of Wp-particle fraction, Wp-supercooled vapor pressure were analyzed. The results suggested the particle scavenging by precipitation is less efficient for PAHs with higher molecular weights, while more volatile PAHs with lower molecular weights deposited on larger atmospheric particles were scavenged more efficiently. The efficiency of Wp was found to be increased with rain intensity. For gas scavenging, the dissolution and adsorption mechanisms shift their relative importance with different supercooled vapor pressure. © 2016.


Li P.-H.,Tianjin University of Technology | Wang Y.,Shandong University | Li Y.-H.,Shandong Environmental Monitoring Center | Li H.-L.,Shandong Environmental Monitoring Center | And 2 more authors.
Advances in Meteorology | Year: 2015

To understand the deposition and transport of PAHs in southern China, a measurement campaign was conducted at a high-elevation site (the summit of Mount Heng, 1269 m A.S.L.) from April 4 to May 31, 2009, and a total of 39 total suspended particulate samples were collected for measurement of PAH concentrations. The observed particulate-bound PAHs concentrations ranged from 1.63 to 29.83 ng/m3, with a mean concentration of 6.03 ng/m3. BbF, FLA, and PYR were the predominant compounds. Good correlations were found between individual PAHs and meteorological parameters such as atmospheric pressure, relative humidity, and ambient temperature. The backward trajectory analysis suggested that particulate samples measured at the Mount Heng region were predominantly associated with the air masses from southern China, while the air masses transported over northern and northwestern China had relative higher PAHs concentrations. Based on the diagnostic ratios and factor analysis, vehicular emission, coal combustion, industry emission, and unburned fossil fuels were suggested to be the PAHs sources at Mount Heng site. However, the reactivity and degradation of individual PAHs could influence the results of PAH source profiles, which deserves further investigations in the future. © 2015 Peng-hui Li et al.


Guan J.,Shandong University | Liu G.,Shandong Institute for Food and Drug Control | Cai K.,Shandong Environmental Monitoring Center | Gao C.,Shandong University | Liu R.,Shandong University
Luminescence | Year: 2015

In order to evaluate the toxicity of multi-walled carbon nanotubes (MWCNTs-COOH) at a molecular level, the effect of MWCNTs-COOH on antioxidant enzyme copper-zinc superoxide dismutase (Cu/ZnSOD) was investigated using fluorescence spectroscopy, UV/vis absorption spectroscopy, circular dichroism (CD) spectroscopy and isothermal titration calorimetry (ITC). By deducting the inner filter effect (IFE), the fluorescence emission spectra and synchronous fluorescence spectra indicated that there were interactions between MWCNTs-COOH and Cu/ZnSOD. Moreover, the microenvironment of the amino acid residues in the enzyme was changed slightly. The UV/vis absorption and CD spectroscopic results showed appreciable conformational changes in Cu/ZnSOD. However, the results of a Cu/ZnSOD activity determination did not show any significant difference. In other words, MWCNTs-COOH has no significant effect on enzyme activity. The ITC results showed that the binding of MWCNTs-COOH to Cu/ZnSOD was a weak endothermic process, indicating that the predominant force of the binding was hydrophobic interaction. Moreover, it was essential to consider the IFE in fluorescence assays, which might affect the accuracy and precision of the results. The above results are helpful in evaluating the oxidative stress induced by MWCNTs-COOH in vivo. © 2014 John Wiley & Sons, Ltd.


PubMed | Shandong Environmental Monitoring Center, Shandong University and Food Republic
Type: Journal Article | Journal: Luminescence : the journal of biological and chemical luminescence | Year: 2015

In order to evaluate the toxicity of multi-walled carbon nanotubes (MWCNTs-COOH) at a molecular level, the effect of MWCNTs-COOH on antioxidant enzyme copper-zinc superoxide dismutase (Cu/ZnSOD) was investigated using fluorescence spectroscopy, UV/vis absorption spectroscopy, circular dichroism (CD) spectroscopy and isothermal titration calorimetry (ITC). By deducting the inner filter effect (IFE), the fluorescence emission spectra and synchronous fluorescence spectra indicated that there were interactions between MWCNTs-COOH and Cu/ZnSOD. Moreover, the microenvironment of the amino acid residues in the enzyme was changed slightly. The UV/vis absorption and CD spectroscopic results showed appreciable conformational changes in Cu/ZnSOD. However, the results of a Cu/ZnSOD activity determination did not show any significant difference. In other words, MWCNTs-COOH has no significant effect on enzyme activity. The ITC results showed that the binding of MWCNTs-COOH to Cu/ZnSOD was a weak endothermic process, indicating that the predominant force of the binding was hydrophobic interaction. Moreover, it was essential to consider the IFE in fluorescence assays, which might affect the accuracy and precision of the results. The above results are helpful in evaluating the oxidative stress induced by MWCNTs-COOH in vivo.


Wang Y.,Shandong University | Li P.-h.,Shandong University | Li H.-l.,Shandong Environmental Monitoring Center | Liu X.-h.,Shandong University | Wang W.-x.,Shandong University
Atmospheric Research | Year: 2010

Polycyclic aromatic hydrocarbons (PAHs) in precipitation samples collected at Mount Taishan were determined by HPLC, to evaluate their concentrations and variations. Individual precipitation events were sampled for 2 years from Sep. 2005 to Aug. 2007. Low concentrations of PAHs were found at the site. Phenanthrene was the most abundant compound with a volume-weighted mean concentration of 33.31 ng/L. The next most abundant compound was fluorene, with a concentration of 16.61 ng/L. Other individual PAHs occurred at concentrations lower than 10 ng/L. The volume-weighted mean concentration of the total PAHs in winter precipitation was much higher than in summer, showing a seasonal variation. Most of the individual PAHs compounds have strong correlations with rainfall amount. Pyrene, benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene and benzo(a)pyrene all had strong correlations with Na+ and Cl-. Diagnostic ratio analysis and factor analysis indicated that the sources of PAHs are mainly from fossil fuel combustion, especially coal. Crown Copyright © 2009.


Chai J.,Shandong University | Xu Q.,Shandong University | Dai J.,Shandong Environmental Monitoring Center | Liu R.,Shandong University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

Clenbuterol (CLB) is a kind of β2-adrenergic agonists which was illegally used as feed additives nowadays. The toxic interaction of CLB with trypsin, an important digestive enzyme, was studied in vitro using multi-spectroscopic methods and molecular modeling methods. CLB was proved to bind with trypsin in S1 pocket, forming a complex driven by the dominant force of H-bond. The binding constant was calculated to be 1.79887 × 10 5 L mol-1 at 289 K and 0.32584 × 105 L mol-1 at 310 K, respectively. The skeleton of trypsin became loosened and unfolded with the amino residues microenvironment changed. The secondary and tertiary structure of trypsin also varied. Molecular modeling studies illustrated specific display of the binding information and explained most of the experiment phenomena. The binding site of CLB induced the fluorescence quenching as well as inhibition of enzyme activity of trypsin. The study confirmed that CLB had potential toxicity on both the structure and function of trypsin and the effects enhanced with the increasing concentration of CLB. © 2012 Elsevier B.V. All rights reserved.


Yang M.,Shandong University | Wang Y.,Shandong University | Chen J.,Shandong University | Li H.,Shandong Environmental Monitoring Center | Li Y.,Shandong Environmental Monitoring Center
Aerosol and Air Quality Research | Year: 2016

In this study, 45 ambient samples were collected in the summer of 2011 and spring of 2012 on Mount Lushan. The concentrations and seasonal distributions of aromatic hydrocarbons and halocarbons were measured and discussed. Moderate concentrations of individual species were found compared with other mountain sites; however, the measured concentrations were much lower than the values reported in cities. For aromatic hydrocarbons, benzene and m/p-xylene were the most abundant species in the spring, while benzene and toluene exhibited the largest contributions in the summer. For halocarbons, the concentrations of 1,2,4-trichlorobenzene, dichlorodifluoromethane and chloromethane were higher than other gases measured in the spring; and dichlorodifluoromethane and chloromethane contributed largest in the summer. The OH loss rates demonstrated that 1,3,5-trimethylbenzene and 1,2,4-trimethylbenzene were the dominant aromatic hydrocarbons for OH loss rates in the spring, while styrene and toluene contributed the largest to reactivity in the summer. For the ozone formation potential (OFP), 1,2,4-trimethylbenzene and m/p-xylene accounted for the largest fraction of the OFPs in the spring (24.3% and 23.7%), while toluene was the most abundant source of OFP (i.e., 43.7%) in the summer. M/p-xylene exhibited large contributions to OFP in both spring and summer (23.7% and 19.2%) of the OFPs. The T/B (0.80 and 0.73 in spring and summer respectively) ratios indicated that the sampled air masses were primarily influenced by automotive emissions. The 36-h backward trajectories of the sampled air masses and the corresponding daily concentrations of individual species suggested that long-range transport had a large effect on the atmosphere at the sampling site. © Taiwan Association for Aerosol Research.


Yang M.,Shandong University | Wang Y.,Shandong University | Liu Q.,Nanjing University | Ding A.,Nanjing University | Li Y.,Shandong Environmental Monitoring Center
Atmosphere | Year: 2015

PM2.5 (Particulate Matter 2.5) samples were collected at Mount Heng and analyzed for polycyclic aromatic hydrocarbons (PAHs). During sampling, a sandstorm from northern China struck Mount Heng and resulted in a mean PM2.5 concentration of 150.61 μg/m3, which greatly exceeded the concentration measured under normal conditions (no sandstorm: 58.50 μg/m3). The average mass of PAHs in PM2.5 was 30.70 μg/g, which was much lower than in the non-sandstorm samples (80.80 μg/g). Therefore, the sandstorm increased particle levels but decreased PAH concentrations due to dilution and turbulence. During the sandstorm, the concentrations of 4- and 5-ring PAHs were below their detection limits, and 6-ring PAHs were the most abundant. Under normal conditions, the concentrations of 2-, 3- and 6-ring PAHs were higher, and 4- and 5-ring PAHs were lower relative to the other sampling sites. In general, the PAH contamination was low to medium at Mount Heng. Higher LMW (low molecular weight) concentrations were primarily linked to meteorological conditions, and higher HMW (high molecular weight) concentrations primarily resulted from long-range transport. Analysis of diagnostic ratios indicated that PM2.5 PAHs had been emitted during the combustion of coal, wood or petroleum. The transport characteristics and origins of the PAHs were investigated using backwards Lagrangian particle dispersion modeling. Under normal conditions, the "footprint" retroplumes and potential source contributions of PAHs for the highest and lowest concentrations indicated that local sources had little effect. In contrast, long-range transport played a vital role in the levels of PM2.5 and PAHs in the high-altitude atmosphere. © 2015 by the authors.


Guan J.,Shandong University | Dai J.,Shandong Environmental Monitoring Center | Zhao X.,Shandong University | Liu C.,Shandong University | And 2 more authors.
Journal of Biochemical and Molecular Toxicology | Year: 2014

The interactions between well-dispersed multiwalled carbon nanotubes (MWCNTs) and catalase (CAT) were investigated. The activity of CAT was inhibited with the addition of MWCNTs. After deducting the inner filter effect, the fluorescence spectra revealed that the tryptophan (Trp) residues were exposed and the fluorescence intensities of CAT increased with the increase in the MWCNTs concentration. At the same time, the environment of the Trp residues became more hydrophobic. The results of UV-vis absorption spectroscopy and CD spectra indicated that the secondary structure of CAT had been changed, and the amino acid residues were located in a more hydrophobic environment. Meanwhile, the UV-vis spectra indicated that the conformation of the heme porphyrin rings was changed. The microenvironment of CAT activity sites may be interfered by MWCNTs. This research showed that MWCNTs could not only contribute to the conformational changes of protein but also change the enzyme function. © 2014 Wiley Periodicals, Inc.

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