Search

Epidemiological studies have corroborated that respiratory diseases, including lung cancer, are related to fine particulate matter (<2.5 μm) (PM 2.5 ) exposure. The toxic responses of PM 2.5 are greatly influenced by the source of PM 2.5 . However, the effects of PM 2.5 from Beijing on bronchial genotoxicity are scarce. In the present study, PM 2.5 from Beijing was sampled and applied in vitro to investigate its genotoxicity and the mechanisms behind it. Human bronchial epithelial cells 16HBE were used as a model for exposure. Low (67.5 μg/mL), medium (116.9 μg/mL), and high (202.5 μg/mL) doses of PM 2.5 were used for cell exposure. After PM 2.5 exposure, cell viability, oxidative stress markers, DNA (deoxyribonucleic acid) strand breaks, 8-OH-dG levels, micronuclei formation, and DNA repair gene expression were measured. The results showed that PM 2.5 significantly induced cytotoxicity in 16HBE. Moreover, the levels of reactive oxygen species (ROS), malondialdehyde (MDA), and cellular heme oxygenase (HO-1) were increased, and the level of glutathione (GSH) was decreased, which represented the occurrence of severe oxidative stress in 16HBE. The micronucleus rate was elevated, and DNA damage occurred as indicators of the comet assay, γ-H2AX and 8-OH-dG, were markedly enhanced by PM 2.5 , accompanied by the influence of 8-oxoguanine DNA glycosylase (OGG1), X-ray repair cross-complementing gene 1 (XRCC1), and poly (ADP-ribose) polymerase-1 (PARP1) expression. These results support the significant role of PM 2.5 genotoxicity in 16HBE cells, which may occur through the combined effect on oxidative stress and the influence of DNA repair genes.

Aerobic granular sludge (AGS) was cultivated in a sequencing batch reactor (SBR). In this study, AGS was broken during the formation process and then mature AGS formed again. The microbial community dynamics during two sludge granulation processes were investigated using high-throughput sequencing to reveal the dominant bacteria beneficial to AGS formation. The abundance dynamics of nitrifying microorganisms were analyzed by a quantitative polymerase chain reaction (qPCR). The results showed that the amount of extracellular protein and polysaccharides increased during two sludge granulation processes. The abundance of ammonia oxidizing archaea (AOA) increased during the first AGS formation process and during the process of AGS maturation. The abundance of ammonia oxidizing bacteria (AOB) decreased during the first AGS formation process, while it maintained a higher abundance than AOA during AGS cultivation. Microbial diversity decreased with AGS formation. The relative abundance of Proteobacteria increased by 12.29% and 5.90% during two sludge granulation processes, respectively. Candidatus Competibacter belonging to Proteobacteria was enriched during two sludge granulation processes, accounting for 14.20% in mature AGS. Overall, extracellular protein and polysaccharides may have contributed to the sludge granulation. Both AOA and AOB might have been involved in ammonia oxidation. This study indicated that Ca. Competibacter might contribute to AGS formation.

Objective: To compare the safety and effectiveness of shovel-shaped electrode transurethral plasmakinetic enucleation of the prostate (PKEP) with those of plasmakinetic resection of the prostate (PKRP) in the treatment of benign prostatic hyperplasia (BPH)., Methods: We retrospectively analyzed the clinical data about 78 BPH patients received in Shanghai Ninth People's Hospital from June 2016 to January 2017, 39 treated by shovel-shaped electrode PKEP and the other 39 by PKRP. We observed the patients for 6 months postoperatively and compared the effects and safety of the two surgical strategies., Results: No statistically significant difference was observed between the PKEP and PKRP groups in the operation time (［69.3 ± 8.8］ vs ［72.2 ± 7.9］ min, P = 0.126), but the former, as compared with the latter, showed a markedly less postoperative loss of hemoglobin (［3.9 ± 2.8］ vs ［13.9 ± 5.2］ g/L, P <0.001) and shorter bladder irrigation time (［12.5 ± 1.2］ vs ［43.4 ± 2.8］ h, P <0.001), catheterization time (［64.0 ± 4.5］ vs ［84.8 ± 3.0］ h, P <0.001) and hospital stay (［3.1 ± 0.3］ vs ［5.5 ± 0.4］ d, P <0.001). There were no statistically significant differences between the PKEP and PKRP groups in the postoperative maximum urinary flow rate (Qmax) (［21.62 ± 1.07］ vs ［21.03 ± 0.96］ ml/s, P = 0.12), International Prostate Symptoms Score (IPSS) (5.85 ± 0.90 vs 6.03 ± 0.81, P = 0.279), quality of life score (QoL) (2.0 ± 0.73 vs 2.28 ± 0.72, P = 0.09), postvoid residual urine volume (PVR) (［19.59 ± 6.01］ vs ［20.21 ± 5.16］ ml, P = 0.629), or the incidence rates of urinary incontinence (2.56% ［1/39］ vs 7.69% ［3/39］, P >0.05) and other postoperative complications., Conclusions: Both PKEP and PKRP are effective methods for the treatment of BPH, but PKEP is worthier of clinical recommendation for a better safety profile, more thorough removal of the prostate tissue, less blood loss, shorter hospital stay, and better improved quality of life of the patient.

In this study, domestic sewage was utilized to cultivate aerobic granular sludge (AGS) in a simultaneous nitrogen and phosphorus removal (SNPR) system. The bacterial population dynamics during the aerobic sludge granulation were investigated to reveal the granulation mechanisms using Illumina MiSeq PE300 high-throughput sequencing. Quantitative real time polymerase chain reactions (PCR) were used to investigate shifts in the abundance of ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA), nitrite-oxidizing bacteria (NOB) and polyphosphate accumulating organisms (PAOs). After cultivation for 100 d, the AGS was compact and demonstrated good SNPR performance. During the AGS formation process, extracellular polysaccharides obviously increased, while extracellular proteins kept relatively stable. The abundance of AOA significantly decreased during the formation of AGS process, while the abundance of PAOs increased. The bacterial diversity increased at first and then decreased during the formation of AGS. The bacterial community changed dramatically during aerobic sludge granulation. Persistent operational taxonomic units (OTUs) accounted for 92.70% of the total sequences. Proteobacteria (31.07%-53.67%), Bacteroidetes (6.70%-16.50%) and Chloroflexi (7.84%-13.36%) were the dominant phyla. Candidatus competibacter was obviously enriched in the AGS formation process (increased from 0.11% in the seed sludge to 35.33% in the AGS) and may play an important role in the formation of AGS.

In this study, the short-term effect of roxithromycin(ROX) on the abundance and diversity of ammonia-oxidizing archaea(AOA) and ammonia-oxidizing bacteria(AOB) based on amoA gene in activated sludge were investigated by high-throughput sequencing and quantitative real-time PCR(qPCR). High-throughput sequencing overcomes the drawbacks of low sequencing depth, significant randomness and great bias of traditional Sanger sequencing. This approach can provide enough sequencing depth to comprehensively investigate the sensitive and insensitive ammonia-oxidizing microorganisms under ROX selective pressure. Lab-scale reactors were operated under ten different ROX levels. The results indicated that the environmental(0.3-30 μg·L -1 ) and medium(300 μg·L -1 and 3000 μg·L -1 ) levels of ROX did not affect ammonia oxidation, while the higher concentration(5000-12000 μg·L -1 ) of ROX showed a significant negative effect on ammonia oxidation. The environmental and medium levels of ROX stimulated the growth of AOA, however, the higher level of ROX decreased the abundance of AOA. In addition, different levels of ROX(except 0.3 μg·L -1 ) caused the decrease of the abundance of AOB, which suggested that AOA was less sensitive than AOB under ROX selective pressure. The results of high-throughput sequencing showed that ROX selective pressure caused the decrease of the numbers of OTUs for AOA and increase of that for AOB. The insensitive AOA, accounting for 57.70%-97.81% of the total sequences, were Candidatus Nitrososphaera gargensis and Candidatus Nitrosoarchaeum koreensis. The insensitive AOB were Nitrosomonas oligotropha, Nitrosospira multiformis, Nitrosomonas watsonii and Nitrosomonas halophilus , accounting for 0.76%-5.10% of the total sequences. These results also indicated that AOA was insensitive to ROX, but AOB was sensitive to ROX. RDA analyses showed that AOA Ca . Nitrososphaera gargensis, Ca . Nitrosoarchaeum koreensis and AOB N. oligotropha, N. watsonii, N. halophilus were positively correlated with ROX concentrations.

Ammonia oxidation is the first and rate-limiting step of nitrification, which was thought to be only performed by ammonia-oxidizing bacteria (AOB). In recent years, ammonia-oxidizing archaea (AOA) was also confirmed to take part in ammonia oxidation. The diversity and abundance of AOA have been investigated in various environments, however, little is known regarding the AOA in the completely autotrophic nitrogen removal over nitrite (CANON) wastewater treatment process. In this study, the abundance and diversity of AOA were investigated in the biofilm and flocculent activated sludge collected in a lab-scale (L) CANON system and a pilot-scale (P) CANON systems, respectively. The quantitative real time PCR (qPCR) was applied to investigate the abundance of AOA and the diversity of AOA was determined by polymerase chain reaction (PCR), cloning and sequencing. The qPCR results showed that the average abundance of AOA amoA gene of L and P was 2.42 x 10(6) copies x g(-1) dry sludge and 6.51 x 10(6) copies x g(-1) dry sludge, respectively. The abundance of AOA in biofilm was 10.1-14.1 times higher than that in flocculent activated sludge. For P system, the abundance of AOA in flocculent activated sludge was 1.8 times higher than that in biofilm. The results indicated that the abundance of AOA might be affected by different sludge morphology. The diversity of AOA in P system was extremely limited, only one OTU was observed, which was classified into Nitrosopumilus subcluster 5.2. The diversity of AOA in L system was higher, eight OTUs were observed, which were classified into five genera: Nitrososphaera subcluster 9, subcluster 8.1, subcluster 4.1, subcluster 1.1 and Nitrosopumilus subcluster 5.2. The diversity and abundance of AOA were different in CANON systems with different sludge morphology. AOA may play an important role in ammonia oxidation in CANON system.

In order to characterize the dense and regular level of aerobic granular sludge (AGS) which was cultivated by different carbon sources, the SEM images of mature AGS were used in the study. The calculation process using Photoshop and Fips2 on fractal characteristics of these granules was built. The lowest box-counting dimension was bulking aerobic granular sludge cultivated by glucose (No. 1), which was 1.794 +/- 0.011; the box-counting dimension of AGS cultivated by peptone (No. 3) and domestic sewage (No. 5) were reached up to 1.866 +/- 0.018 and 1.880 +/- 0.015. The boundary box-counting dimension of the AGS was also calculated and the average value was 1.14. The AGS cultivated by beer (No. 6) was more regular in shape and the boundary box-counting dimension was 1.115 +/- 0.003. The AGS cultivated by landfill leachate (No. 7) was the most irregular in shape. This study indicates that fractal dimension provides an approach for quantification of dense and regular level of AGS, furthermore, it could be used to characterize the status of AGS, such as bulking.

Aerobic granular sludge (AGS) for simultaneous nitrogen and phosphorus removal (SNPR) was cultivated and studied in two lab-scale sequencing batch reactors (named as A & B) treating real domestic wastewater, additional carbon (sodium propionate and sodium acetate for A, glucose for B) was added to make the ratio of COD:N:P as 360:60:6, good SNPR was achieved at normal (18-27 degrees C) and low temperature (9-13 degrees C). The microbial community composition and distribution, distribution of cells and extracellular polymeric substances (EPS) and morphologies of the AGS were investigated using fluorescence in situ hybridization (FISH), in situ fluorescent staining and scanning electron microscope (SEM), respectively. FISH results showed that ammonium-oxidizing bacteria comprised 12% of all the bacteria and were mainly located at the outer parts of the granules; phosphates accumulating organisms comprised 40% of all the bacteria and were mainly located in the inner parts of the granules. Nitrification was the rate controlling step; denitrifying phosphate accumulating organisms inside the granular sludge might be responsible for denitrification in the aerobic phase, which enabled effective SNPR. Live/dead fluorescent staining results showed that dead cells were distributed throughout the granules and live cells were principally distribution of polysaccharide (including alpha-mannopyranosyl, alpha-glucopyranosyl sugars and beta-D-glucopyranose polysaccharides) of EPS in AGS were influenced by different carbon sources, but the contents and distributions of protein and lipids were not, the contents of protein was the largest. Polysaccharide was responsible for the formation and maintenance of aerobic granular sludge. SEM results showed that bacilli and cocci were the main bacteria in the granules of A and B, respectively. Carbon sources affected the bacteria type and the SNPR efficiency, sodium propionate and sodium acetate were better than glucose.

The simultaneous nitrogen and phosphorus removal (SNPR) from real domestic wastewater using aerobic granular sludge (AGS) has been investigated. The effect of temperature changes on the SNPR of AGS was also studied. Two lab-scale sequencing batch reactors (SBRs), named as A and B, were operated for 254 days in alternating anaerobic-aerobic mode. The AGS was cultivated in 20 days using settling time as selection pressure. From the 42nd day onwards, additional carbon (acetate and peptone for A, glucose for B) were added to make the ratio of COD:N:P as 360:60:6. The SNPR by AGS was achieved for 4 months, and the removal ratios of ammonia, total inorganic nitrogen and phosphorus of A were reached to 98.42%, 74.25% and 94.79%, respectively; the removal ratios of ammonia, total inorganic nitrogen and phosphorus of B were reached to 99.45%, 75.96% and 95.60%, respectively. Then, the temperature decreased to 9-13 degrees C, which seriously affected the efficiency of SNPR. The removal efficiencies of SNPR of reactor A and B were recovered after 35 days and 49 days, respectively, and the removal ratios of ammonia, total inorganic nitrogen and phosphorus of A were reached to 96.33%, 79.49% and 99.68%, respectively; the removal ratios of ammonia, total inorganic nitrogen and phosphorus of B were reached to 93.85%, 76.44% and 98.44%, respectively. PAOs and DNPAOs together completed the phosphorus removal and made phosphorus removal faster than nitrogen removal. Nitrification was the rate limiting step for SNPR. The low temperature made the anoxic zone in AGS decrease, together with the absence of PHAs, made denitrification could not complete.

In order to investigate the effects of decreasing settling time and biofilm on the rapid start-up of aerobic granular sludge reactor for nitrification, the real domestic wastewater was treated in three sequencing batch reactors (SBR, named as R1, R2 and R3) and one sequencing batch airlift reactor (SBAR, named as R4). After decreasing the settling time from 20 min directly to 2, 4 and 2 min respectively in R1, R2 and R4, for the reason that the selective pressure of settling velocity was so strong that the activated sludge was all washed out of the reactors, the three SBRs lost their function of treating wastewater. Then the biofilm grew on the walls of the three reactors, and lots of soft granular-like sludge appeared in the reactors, 35 - 40 days later. The biofilm made the effluent ammonia of R1, R2 and R4 lower than 1 mg/L. The soft granular-like sludge was not the aerobic granular sludge, but there were lots of rotifers both around the soft granular-like sludge and the aerobic granular sludge. The phenomena showed that aerobic granular sludge was one type of biofilm. In R3 the settling time was shortened gradually from 20 min to 8, 6, 5 and 4 min. When the settling velocity was 10 cm/min, the activated sludge began to granulate, and when the settling velocity reached 12 cm/min, the aerobic granular sludge became dominant in the reactor, but the sludge floc coexisted with aerobic granular sludge. It took 33 days to cultivate aerobic granules in R3. The average diameter of the aerobic granular sludge was 0.5 mm, the ratio of aerobic granular sludge to sludge floc by weight was 2:1, and the ammonia oxidized rate of aerobic granular sludge was 5 times as the sludge floc's.