Effects of biochar on the growth of Vallisneria natans in surface flow constructed wetland.

To improve the nitrogen and phosphorus removal efficiency of surface flow constructed wetlands (SFCWs), biochar was added to an SFCW matrix. The effects of adding different amounts of biochar on water purification, the growth of Vallisneria natans (V. natans), and microbial mechanisms were explored through SFCW simulation experiments. The results showed that through the joint action of biochar and V. natans, the concentrations of total nitrogen, total phosphorus, and ammonia nitrogen in the effluent significantly decreased. The total biomass, relative growth rate, and chlorophyll content of V. natans were significantly reduced by adding biochar (≥20%, v/v), as the root activity and the root to leaf biomass ratio slightly increased at first and then decreased. The carbon and nitrogen contents of V. natans slightly increased with the addition of biochar (≥10%, v/v), but the phosphorus content slightly decreased. Moreover, the nitrogen content of the matrices decreased significantly over time (P<0.05), and the phosphorus content in the matrix showed an increasing trend in the same period. In addition, the microbial 16S rDNA sequencing results indicated that the diversity and abundance of the microbial community in the matrix of the biochar-added SFCW tended to decrease. Nevertheless, the abundance of functional bacteria related to nitrogen and phosphorus removal (i.e., Pseudomonas and Dechloromonas) slightly increased, which would benefit denitrification and dephosphorization in the SFCW. Hence, the addition of biochar to the SFCW matrix facilitated the improvement of effluent water quality, while excessive biochar addition (≥10%, v/v) restrained the growth of V. natans but did not cause death. This conclusion provides valid data support regarding the ability of biochar-added SFCW to purify lightly contaminated water.

The interaction between RAGE gene polymorphisms and HPV infection in determining the susceptibility of cervical cancer in a Chinese population.

AIM: To explore the possible association between the receptor for advanced glycation end products (RAGE) gene polymorphisms and the risk of cervical cancer. METHOD: We enrolled 488 patients with cervical squamous cell carcinoma and 715 age-matched female healthy subjects as controls. Human Papillomavirus (HPV) infection and four RAGE gene polymorphisms (-429T>C, -374T>A, 1704G>T, and 82G>S) in all subjects were determined. RESULTS: The genotype distributions and allele frequencies of -429T>C, 1704 T>G and -374T>A were not significantly different between cervical cancer patients and controls (all P> 0.05). For 82G>S polymorphisms, the genotype distributions and allele frequencies were significantly different between the two groups. The cervical cancer patients had markedly higher percentage of 82SS carriage than controls. The logistic regression analysis showed that the 82SS genotype was associated with significantly elevated risk for cervical cancer, adjusted odds ratio (OR) was 1.98, (P< 0.001). In addition, the 82SS carriers had significantly lower serum soluble RAGE (sRAGE) levels than 82GS and 82GG. The polymorphisms of -429T>C, -374T>A and 1704T>G did not affect the cervical cancer risk and the serum sRAGE levels. When all the cancer patients were stratified by HPV infection status, the 82GS and 82SS genotype carriers in the HPV infection subgroup had increased risk for cervical cancer versus 82GG (OR=1.68 and 1.74, respectively, both P<0.05). This trend was not observed in the subgroup with no detectable HPV DNA. CONCLUSION: Our results suggest that the RAGE 82G>S polymorphisms, interacting with HPV infection, are implicated in the occurrence of cervical cancer.