[Atmospheric Pollution Characteristics and Inhalation Exposure Risk of Nitrated Polycyclic Aromatic Hydrocarbons in PM2.5 at the Ningdong Energy and Chemical Industry Base, Northwest China].

Atmospheric PM2.5 samples were collected by using the active sampling method to investigate the pollution characteristics of nitrated polycyclic aromatic hydrocarbons (NPAHs) at the Ningdong Energy and Chemical Industry Base, Northwest China. Furthermore, the primary sources and the contributions of secondary formation sources as well as the inhalation exposure risks were identified. The main results were as follows. The concentration levels of ∑12NPAHs in PM2.5 ranged from 2.06 ng·m-3 to 37.14 ng·m-3 at the Ningdong Energy and Chemical Industry Base. The average concentrations of ∑12NPAHs were (25.57±5.76) ng·m-3 in winter and (6.22±1.74) ng·m-3 in summer for the Baofeng sampling site associated with the energy industry. The average concentrations of ∑12NPAHs were (7.13±1.44) ng·m-3 in winter and (2.58±0.39) ng·m-3 in summer for the Yinglite sampling site associated with chemical and electricity industries. The levels of ∑12NPAHs in PM2.5 were higher in winter than those in summer because of the increased heating in winter. Atmospheric pollution levels of NPAHs at the Baofeng sampling site were generally higher than those at the Yinglite sampling because of the higher primary NPAHs emissions from coal mining and coke production in Baofeng compared with those from the chemical industry in Yinglite. The calculated nocturnal/diurnal ratios revealed that the concentrations of ∑12NPAHs in PM2.5 during the summer season were higher in the daytime than those in the nighttime, but the opposite trend occurred in winter, thus indicating that secondary formation processes made more contributions to NPAHs during summer in the daytime. The congener profiles of NPAHs were mainly composed of primary emission markers such as 2-nitrofluorene (2N-FLO) and 6-nitrochrysene (6N-CHR), which were the predominant ones in winter and summer for both the Baofeng and Yinglite sampling sites. Total proportions of 2N-FLO and 6N-CHR were 46% in winter and 73% in summer for Baofeng and 59% in winter and 55% in summer for Yinglite, respectively. Meanwhile, 3N-PHE, which is a marker compound of secondary formation processes, accounted for a higher percentage in summer especially at Yinglite. This finding revealed that the chemical production at Yinglite was associated with higher precursor emissions than that of Baofeng, and thus, more NPAHs were derived from secondary formation processes. Moreover, ∑12NPAHs/∑16PAHs ratios were calculated to identify the potential sources of NPAHs across the city. The results indicated that higher environmental temperatures in summer promoted the degradation of PAHs and secondary formation of NPAHs, and thus, secondary formation contributed more to NPAHs in summer than in winter. Furthermore, lung cancer risks induced by inhalation exposures to ∑5NPAHs were assessed based on the BaP equivalent toxicity factor. The results showed that the lung cancer risk values of ∑5NPAHs were (3.06×10-5±1.36×10-5) in winter and (1.79×10-5±0.80×10-5) in summer for the Baofeng sampling site, while the risk values were (2.85×10-5±1.20×10-5) in winter and (1.86×10-5±0.83×10-5) in summer for the Yinglite sampling site. Notably, the lung cancer risk values in our study for both sampling sites were higher than the standard limit value (1.00×10-5) of the California Environmental Protection Agency, which indicates that the local population at the Ningdong Energy and Chemical Industry Base has been subjected to potentially elevated lung cancer risks due to inhalation exposures to PM2.5-bound NPAHs.

[Atmospheric Dry Deposition Fluxes and Sources of Polycyclic Aromatic Hydrocarbons in Lanzhou Valley, Northwest China].

The atmospheric dry deposition flux pollution levels were determined and the sources apportioned for 15 US EPA priority polycyclic aromatic hydrocarbons (PAHs) collected at 13 sampling sites in the Lanzhou valley using passive sampling techniques. The results are as follows. The annual atmospheric dry deposition fluxes ranged from 7.48 to 53.94 µg·(m2·d)-1, with a mean of 18.65 µg·(m2·d)-1. The highest flux levels for both the heating and non-heating seasons, 60.85 µg·(m2·d)-1 and 47.03 µg·(m2·d)-1, respectively, appeared at the traffic site (Donggang Bridge), where the heaviest traffic in the Lanzhou valley occurs. The lowest flux levels of 8.16 µg·(m2·d)-1 and 6.80 µg·(m2·d)-1 for the heating and non-heating seasons, respectively, were found at Baita Mountain, which has a higher percentage of vegetation cover. Meanwhile, the flux levels at the background site (Guantangou Mountain) were significantly lower than those of the other sampling sites. For dry deposition, the PAH components Phe, Flua, Flu, and Pyr were dominant in the heating and non-heating periods, and the sums of the percentages of 3- and 4-ring PAHs were 87.53% for the heating season and 82.73% for the non-heating season. Moreover, the percentage of 5- and 6-ring PAHs for the non-heating period was higher than that for the heating period, which may be because the lighter PAHs were easily volatilized, and thus escaped. Furthermore, the sources of atmospheric dry deposition were identified by principal component analysis (PCA). The results of source apportionment showed that the main atmospheric PAH dry deposition in the Lanzhou valley were from vehicle exhaust emissions, coal combustion, and the coking industry. In further detail, coal combustion and the coking industry contributed most of the PAH dry deposition emissions during the heating period except for the traffic area site of Donggang Bridge, whereas vehicle exhaust was the dominant contributor during the non-heating season. In addition, the annual average dry deposition velocities of atmospheric PAHs were calculated using the dry deposition model for three sites: 0.20 cm·s-1 downtown (Environmental Protection Agency of Lanzhou; JCZ), 0.15 cm·s-1 in an industrial area (Lanyuan Hotel of Xigu; LLH), and 0.17 cm·s-1 in a traffic area (the Staff Hospital of Gansu Province; ZGH), of which the latter two were relatively lower because of comprehensive meteorological factors such as wind speed, temperature, and land use categories. Regarding the dry deposition flux values of the 3- and 4-ring PAHs, the simulated values were a bit larger than the observed values, but all were at the same level of magnitude. However, the simulated flux values were closer to their observed values for 4-ring PAHs than for 3-ring PAHs, which indicated that 3-ring PAHs were lost more easily than 4-ring PAHs were during monitoring.

Effect of various intervention factors on MMP-3 and TIMP-1 level in synovial fluid in knee joints with osteroarthritis / 中南大学学报(医学版)

OBJECTIVE@#To examine the expression of MMP-3 and TIMP-1 in the synovial fluid in knee joints with osteoarthritis before and after being treated with hyaluronic acid(HA), glucosamine sulfate(GS) and arthroscopic de bridment(AD), and to explore the therapeutic mechanism.@*METHODS@#Sixty patients (64 knees) with osteoarthritis(OA) were randomly divided into HA group AD group and GS+AD group. Some patients from the HA group and the GS+HA group were selected, and served as HA' group and GS+HA' group. The expression of MMP-3 and TIMP-1 in the synovial fluid was measured by enzyme-linked immunosorbent assay (ELISA) before and after 4 week and 6 month therapy.@*RESULTS@#The level of MMP-3 and the ratio of MMP-3/TIMP-1 in the synovial fluid decreased after being treated for 4 weeks, and the effect on MMP-3 and MMP-3/TIMP-1 lasted for 6 months in the HA group and the GS+HA groups. The levels of TIMP-1 increased significantly after being treated for 4 weeks only in the GS+HA group. The level of MMP-3 and the ratio of MMP-3/TIMP-1 in the synovial fluid decreased, but the level of TIMP-1 increased after being treated for 4 weeks, and the effect on MMP-3 and MMP-3/TIMP-1 lasted for 6 months. The level of MMP-3 and the ratio of MMP-3/TIMP-1 in the synovial fluid increased after being treated for 6 months compared with those for 4 weeks. The level of TIMP-1 increased in the GS group more than that in the HA group after being treated for 4 weeks. The level of TIMP-1 increased in the AD group more than that in the HA' group and the GS+HA' group after being treated for 4 weeks.@*CONCLUSION@#(1) HA, GS and AD all can decrease the level of of MMP-3 and the ratio of MMP-3/TIMP-1 in the synovial fluid in knee joints with OA. (2) The level of TIMP-1 in the synovial fluid has no difference before and after being treated with HA. The AD group and GS group can increase the level of TIMP-1, which indicates that the AD group or GS group might produce better therapeutic effect. (3) The level of TIMP-1 increased in the AD group is more than that in the HA' group and the GS+HA' group after being treated for 4 weeks, which indicates that the AD group might get better therapeutic effect than the other 2 groups. (4) One of the most important mechanisms of HA, GS and AD in treating OA might be attributed to the expression of MMPs and TIMPs in knee joints with OA.

Preliminary study on treating patellar instability guided by arthroscopy / 中南大学学报(医学版)

OBJECTIVE@#To explore the operation method in treating patellar instability guided by arthroscopy and to evaluate its therapeutic effects.@*METHODS@#Thirty-two patients (34 knees) with patellar instability including 2 patellar tilt (2 knees), 26 (27 knees) patellar subluxation, and 4 (5 knees) patellar dislocation, diagnosed by clinical and arthroscopical standard, were treated with anterior transfer of the gracilis or medial transfer of the tibial tuberosity based on the lateral retinacular release and medial tightening.@*RESULTS@#Twenty-eight patients were followed up for 5-87 (mean 36.6) months. The excellence rates was 92.8%.@*CONCLUSION@#The patellofemoral alignment can be seen directly and dynamically under the arthroscopy. The combinational treatment including anterior transfer of the gracilis in repairing patellar instability can avoid the recurrence effectively and get satisfactory results.