Pollutants removal, greenhouse gases emission and functional genes in wastewater ecological soil infiltration systems: influences of influent surface organic loading and aeration mode.

The influences of influent surface organic loading rate (SOLR) and aeration mode on matrix oxygen, organic matter, nitrogen, phosphorus removal, greenhouse gases emission and functional gene abundances in lab-scale wastewater ecological soil infiltration systems (WESISs) were investigated. In WESISs, intermittent or continuous aeration improved oxygen supply at 50 cm depth and hardly changed anaerobic condition below 80 cm depth, which enhanced chemical oxygen demand (COD), NH4+-N, total nitrogen (TN) removal, the abundances of bacterial 16S rRNA, amoA, nxrA, narG, napA, nirK, nirS, qnorB, nosZ genes and reduced CH4, N2O conversion efficiencies with SOLR of 16.9 and 27.6 g BOD/(m2 d) compared with non-aeration. Increased SOLR resulted in high TN removal, low N2O emission in aeration WESIS, which was different from non-aeration WESIS. High average COD removal efficiency of 90.7%, NH4+-N removal efficiency of 87.0%, TN removal efficiency of 84.6%, total phosphorus (TP) removal efficiency of 93.1% and low average N2O emission rate of 12.8 mg/(m2 d) were achieved with SOLR of 16.9 g BOD/(m2 d) in intermittent aeration WESIS. However, continuous aeration WESIS obtained high average removal efficiencies of 90.1% for COD, 87.5% for NH4+-N, 84.1% for TN, 92.9% for TP and low average emission rate of 13.1 mg/(m2 d) for N2O with SOLR of 27.6 g BOD/(m2 d). Aeration could be an optional strategy for WESISs to achieve high pollutants removal and low CH4, N2O emission when treating wastewater with high SOLR.

Role of core protein mutations in the development of occult HBV infection.

BACKGROUND & AIMS: Occult HBV infection (OBI) is associated with transfusion-transmitted HBV infection and hepatocellular carcinoma. Studies on OBI genesis have concentrated on mutations in the S region and the regulatory elements. Herein, we aimed to determine the role of mutations in the core region on OBIs. METHODS: An OBI strain (SZA) carrying 9 amino acid (aa) substitutions in the core protein/capsid (Cp) was selected by sequence alignment and Western blot analysis from 26 genotype B OBI samples to extensively explore the impact of Cp mutations on viral antigen production in vitro and in vivo. RESULTS: A large panel of 30 Cp replicons were generated by a replication-competent pHBV1.3 carrying SZA or wild-type (WT) Cp in a 1.3-fold over-length of HBV genome, in which the various Cp mutants were individually introduced by repairing site mutations of SZA-Cp or creating site mutations of WT-Cp by site-directed mutagenesis. The expression of HBcAg, HBeAg, and HBsAg and viral RNA was quantified from individual SZA and WT Cp mutant replicons in transfected Huh7 cells or infected mice, respectively. An analysis of the effect of Cp mutants on intracellular or extracellular viral protein production indicated that the W62R mutation in Cp had a critical impact on the reduction of HBcAg and HBeAg production during HBV replication, whereas P50H and/or S74G mutations played a limited role in influencing viral protein production invivo. CONCLUSIONS: W62R and its combination mutations in HBV Cp might massively affect HBcAg and HBeAg production during viral replication, which, in turn, might contribute to the occurrence of OBI. LAY SUMMARY: Occult hepatitis B virus infections (OBIs) have been found to be associated with amino acid mutations in the S region of the HBV, but the role of mutations in the core protein (Cp) remains unclear. In this study, an OBI strain (SZA) carrying 9 amino acid substitutions in Cp has been examined comprehensively in vitro and in vivo. The W62R mutation in Cp majorly reduces HBcAg and HBeAg production during HBV replication, potentially contributing to the occurrence of OBI.

[Epidemiological survey of high-risk human papillomavirus among 2501 woman].

OBJECTIVE: To survey the prevalence of high-risk human papillomavirus (HPV) in woman in Guangzhou during the period from 2013 to 2014. METHODS: A total of 2501 women in Guangzhou seeking medical attention in our hospital underwent high-risk HPV genotype screening of cervical specimens using real-time PCR. RESULTS: The prevalence of high-risk HPV infection among the women was 14.85% (146/983) in the year 2013, similar to the rate of 14.56% (221/1518) in 2014 (Χ(2)=0.041, P=0.839); no significant differences were found in the high-risk HPV infection rates between different age groups in either 2013 (Χ(2)=2.916, P=0.572) or 2014 (Χ(2)=6.494, P=0.165). The constituent ratio of the 13 types of high-risk HPV showed no significant difference between 2013 and 2014 (Χ(2)=11.872, P=0.452). The 13 HPV genotypes detected, listed in a descending order of the constituent ratios, included HPV-52, -16, -58, -56, -39, -51, -68, -59, -31, -35, -18, -33 and -45 in 2013, and were HPV-52, -16, -58, -68, -18, -51, -56, -39, -31, -33, -59, -35 and-45 in 2014. CONCLUSION: We report a high prevalence of high-risk HPV among women in Guangzhou, which suggests the necessity of screening for high-risk HPV-DNA among women at all ages for prevention and early detection of cervical cancer.