Study on the removal and degradation mechanism of microcystin-LR by the UV/Fenton system.

Microcystin-LR (MC-LR) is highly hepatotoxic and potentially carcinogenic to humans. Therefore, removing MC-LR from water bodies is of paramount importance. This study aimed to investigate the removal efficacy of the UV/Fenton system on MC-LR from copper-green microcystin and to explore its degradation mechanism in simulated real algae-containing wastewater. The results showed that at an initial concentration of 5 µg·L-1, a combination of 300 µmol·L-1 H2O2, 125 µmol·L-1 FeSO4, and 5 min of UV irradiation under average radiation intensity of 48 µW·cm-2 resulted in a removal efficiency of 90.65 % for MC-LR. The reduction of extracellular soluble microbial metabolites of Microcystis aeruginosa confirmed the UV/Fenton method's degradation efficiency for MC-LR, while the observation of the functional group CH and OCO in the treatment group indicated effective binding sites in the coagulation process. However, the presence of humic substances in algal organic matter (AOM) and some proteins and polysaccharides in the algal cell suspension competed with MC-LR for HO·, resulting in a decreased removal effect (78.36 %) in simulated actual algae-containing wastewater. These quantitative results provide an experimental basis and theoretical foundation for controlling cyanobacterial water blooms and ensuring drinking water quality safety.

[Remediation Potential of Ageratum conyzoides L. on Cadmium Contaminated Farmland].

To evaluate the remediation potential of Ageratum conyzoides L. on cadmium (Cd) contaminated farmland soil, the Cd-containing plants and root were collected and analyzed by field investigation, original pot experiment, and field experiment. The enrichment factor and removal rate of Ageratum conyzoides L. was calculated. The results showed that the maximum Cd content in the leaves of Ageratum conyzoides L. growing in soil of different lead-zinc mines was 77.01 mg·kg-1. In the high-concentration Cd soil treatment (T2), Cd content of the above-ground of Ageratum conyzoides L. was 69.71mg·kg-1, and Cd enrichment coefficient was 6.09. In the low-concentration Cd soil treatment (T1), the enrichment characteristics of Cd (Ageratum conyzoides L.) are consistent with the enrichment characteristics of Cd under high concentration conditions. Ageratum conyzoides L. exhibits stable accumulation characteristics for Cd. In the field experiment, the average Cd content of Ageratum conyzoides L. was 21.13 mg·kg-1, and the enrichment coefficient was 6.93. The removal rate of the three planting Ageratum conyzoides L. per mu of soil using the Ageratum conyzoides L. to repair Cd contaminated soil was 13.2%-15.6%. The use of Ageratum conyzoides L. to repair Cd pollution in farmland has a good prospect for engineering application.

[Long-term Efficacy and Ocular Surface of Pterygium Excision Combined with Autologous Corneal Limbal Stem Cell Transplantation in Treatment of Pterygium].

PURPOSE: To evaluate the long-term efficacy of pterygium excision combined with autologous corneal limbal stem cell transplantation in the treatment of pterygium. METHODS: Fifty five patients (57 eyes) diagnosed with primary pterygium undergoing pterygium excision combined with autologous corneal limbal stem cell transplantation between December 2003 and December 2008 were enrolled in this study. Postoperative follow-up endured for 2-8 years, 5.3 years on average. The wound healing, clinical efficacy and postoperative complications were observed. RESULTS: During early stage after surgery, all patients presented with varying degree of hyperemia, edema and sense of foreign body, which were gradually mitigated 3-5 d later and completely recovered in approximately 1 week. The corneal wound was completely epithelized within 4-7 d, 4.83 d on average. Seven patients had persistent ocular surface irritation symptoms after surgery, one case had residual fibrous tissues and four patients developed superficial corneal scars. Postoperative follow-up endured for 2-8 years, 5.3 years on average. Eight patients (8 eyes) recurred with a recurrence rate of 13.11%. In all patients, postoperative OSDI score was significantly decreased at 1-year reexamination. OSDI score and constitution ratio significantly differed between two groups (both P < 0.05). At postoperative 5 years, OSDI score was slightly lower compared with that in last year with no statistical significance (P > 0.05). At post-operative 1- and 5-year, basic tear secretion was (12.95 ± 4.03) mm and (12.68 ± 4.77) mm, tear film break-up time was (10.55 ± 4.13) s and (10.03 ± 4.64) s. Both indexes were significantly improved compared with (9.48 ± 3.34) mm and (8.14 ± 3.57) s before surgery (all P < 0.05). CONCLUSION: Pterygium excision combined with autologous corneal limbal stem cell transplantation is an efficacious treatment of pterygium with mild postoperative symptoms, rapid recovery, low long-term recurrence rate and high efficacy.

Neopterin negatively regulates expression of ABCA1 and ABCG1 by the LXRα signaling pathway in THP-1 macrophage-derived foam cells.

To investigate the effects of neopterin on ABCA1 expression and cholesterol efflux in human THP-1 macrophage-derived foam cells, and to explore the role of the liver X receptor alpha (LXRα) involved. In the present study, THP-1 cells were pre-incubated with ox-LDL to become foam cells. The protein and mRNA expression were examined by Western blot assays and real-time quantitative PCR, respectively. Liquid scintillation counting and high performance liquid chromatography assays were used to test cellular cholesterol efflux and cholesterol content. Neopterin decreased ABCA1 expression and cholesterol efflux in a time- and concentration-dependent manner in THP-1 macrophage-derived foam cells, and the LXRα siRNA can reverse the inhibitory effects induced by neopterin. Neoterin has a negative regulation on ABCA1 expression via the LXRα signaling pathway, which suggests the aggravated effects of neopterin on atherosclerosis.