[Accumulation Characteristics and Release Regularity of Nutrients in Sediments of a Surface-flow Constructed Wetland After Long-term Operation].

Sediments serve as an important carrier during the migration and transformation of pollutants in surface-flow constructed wetlands. Exploring the accumulation characteristics and release patterns of nutrients is of great significance for assessing the purification functions of constructed wetlands after long-term operation. The contents of total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP) in sediments at various locations of the 5-year-old Yanlong Lake surface-flow constructed wetland were analyzed and static release experiments with cylindrical core samples were carried out. The results showed that after five years, sediments at this site have become moderately polluted and the nutrient accumulation level is mainly being affected by the influent flow, water depth, and plant effects. Additionally, ① nutrients in sediments were found to increase along the flow direction; ② they also increase as the depth of overlying water increases and are relatively affected by the carbon; ③ healthier growth of the wetland plants could lead to more nutrients being accumulated in sediments. The release trend of nutrients fell after a rise and basically reached equilibrium after 20 days, and the release rate was mainly affected by the accumulation level of nutrients, which is similar to the trend in light nutrient containing reservoirs. Plant residues contained in the sediments were associated with the stronger release of nutrients. These results can provide a scientific basis for solutions aimed at maintaining the purification capacity of long-running surface-flow constructed wetlands.

[Roles of monocyte chemoattractant protein-1, RANTES and Fractalkine on promoting vulnerability of atherosclerotic plaques].

OBJECTIVE: To elucidate the roles of monocyte chemotactic factors (MCP-1, RANTES and Fractalkine) on the vulnerability of atherosclerotic plaques in patients with stable (SAP) and unstable angina pectoris (UAP). METHODS: Patients with SAP (n = 50) and UAP (n = 50) underwent coronary angiography (CAG) and intravenous ultrasound (IVUS) were included in the study. Monocyte chemotaxis was assayed by the transwell chamber. Concentrations of hs-CRP, MCP-1, RANTES and Fractalkine were measured by Enzyme-linked-immunosorbent assay (ELISA). mRNA expression of MCP-1, RANTES and Fractalkine in the monocytes was detected by RT-PCR. RESULTS: IVUS evidenced soft lipid plaques in 48% UAP patients and in 16% SAP patients (P < 0.05). SAP patients had mainly fibrous and mixed plaques. Plaque burden and vascular remodeling index were significantly higher in UAP patients than in SAP patients (P < 0.01). The averaged number of migrated monocytes in the UAP patients were higher than that in patients with SAP (P < 0.01). Concentration of hs-CRP, MCP-1, RANTES and Fractalkine were significantly higher in UAP patients than those of SAP patients (P < 0.05 or P < 0.01). mRNA expression of MCP-1, RANTES and Fractalkine in patients with UAP was significantly higher than those of SAP patients (P < 0.05). CONCLUSION: Upregulated monocyte chemotactic factors (MCP-1, RANTES and Fractalkine) might promote coronary plaque vulnerability in UAP patients.

[Purification capacity of ditch wetland to agricultural non-point pollutants].

Ditch wetlands have the capacity to remove and purify non-point pollutants from agricultural drainage by sediment retention, plant absorption and microorganism decomposition. Phragmites communis and Zizania latifolia are two main kinds of plants growing naturally in ditch wetlands in the lower reaches of the Yangtze River. They can absorb N and P efficiently, which is the main mechanism of non-point source pollutants purification by wetlands. The harvest of Phragmites communis and Zizania latifolia will take away 463-515 kg/hm2 of N and 127-149 kg/hm2 of P each year, it equal to N and P discharged from 2.3-3.2 hm2 and 1.3-3.0 hm2 of fields respectively in this area. The absorption and decomposition capacity of Zizania latifolia wetland is higher than Phragmites communis wetland. After harvest of plants, wetlands are uncovered to sunlight and oxygen that speeds the transportation and decomposition of nutrients. The amount of organic matters, TN and TP are higher in sediment of harvested area than in that of control. Therefore, seasonal harvest of plants is an efficient measure for wetlands to purify nutrients and alleviate eutrophication of lakes.