Insight into the microbial community of denitrification process using different solid carbon sources: Not only bacteria.

There is a lack of understanding about the bacterial, fungal and archaeal communities' composition of solid-phase denitrification (SPD) systems. We investigated four SPD systems with different carbon sources by analyzing microbial gene sequences based on operational taxonomic unit (OTU) and amplicon sequence variant (ASV). The results showed that the corncob-polyvinyl alcohol sodium alginate-polycaprolactone (CPSP, 0.86±0.04 mg NO3--N/(g·day)) and corncob (0.85±0.06 mg NO3--N/(g·day)) had better denitrification efficiency than polycaprolactone (PCL, 0.29±0.11 mg NO3--N/(g·day)) and polyvinyl alcohol-sodium alginate (PVA-SA, 0.24±0.07 mg NO3--N/(g·day)). The bacterial, fungal and archaeal microbial composition was significantly different among carbon source types such as Proteobacteria in PCL (OTU: 83.72%, ASV: 82.49%) and Rozellomycota in PVA-SA (OTU: 71.99%, ASV: 81.30%). ASV methods can read more microbial units than that of OTU and exhibit higher alpha diversity and classify some species that had not been identified by OTU such as Nanoarchaeota phylum, unclassified_ f_ Xanthobacteraceae genus, etc., indicating ASV may be more conducive to understand SPD microbial communities. The co-occurring network showed some correlation between the bacteria fungi and archaea species, indicating different species may collaborate in SPD systems. Similar KEGG function prediction results were obtained in two bioinformatic methods generally and some fungi and archaea functions should not be ignored in SPD systems. These results may be beneficial for understanding microbial communities in SPD systems.

Seasonal distribution characteristics and ecological risk assessment of phthalate esters in surface sediment of Songhua River basin.

Phthalic acid esters (PAEs) are typical industrial chemicals used in China. PAEs have received considerable attention because of their ubiquity and potential hazard to humans and the ecology. The spatiotemporal distributions of six PAEs in the surface sediments of the Songhua River in the spring (March), summer (July), and autumn (September) are investigated in this study. The total concentration of phthalic acid esters (∑6PAEs) ranges from 1.62 × 102 ng g-1 dry weight (dw) to 3.63 × 104 ng g-1·dw, where the amount in the spring is substantially higher (p < 0.01) than those in the autumn and summer. Seasonal variations in PAEs may be due to rainfall and temperature. The ∑6PAEs in the Songhua River's upper reaches are significantly higher than those in the middle and lower reaches (p < 0.05). Dibutyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) are the two most abundant PAEs. The ecological hazard of five PAEs is assessed using the hazard quotient method. DBP and DEHP pose moderate or high ecological risks to aquatic organisms at various trophic levels. PAEs originate primarily from industrial, agricultural, and domestic sources. Absolute principal components-multiple linear regression results indicate that agricultural sources are the most dominant contributor to the ∑6PAEs (53.7%). Guidelines for controlling PAEs pollution in the Songhua River are proposed.

Novel slow-release carbon source improves anodic denitrification and electricity generation efficiency in microbial fuel cells.

MFC anodic denitrification is more suitable for the coexistence of organic matter and nitrate in actual sewage, but the traditional carbon source has some problems such as high cost and difficulty of dosage control in MFC. Herein, corncob and polycaprolactone (PCL) were mechanically pulverized and mixed in the system of polyvinyl alcohol and sodium alginate, and cross-linked to prepare slow-release carbon source fillers (CPSP), which were added to the MFC anolyte to realize the coupling of solid-phase denitrification and anodic denitrification. Results showed the start-up period of MFC experimental group (MFC-C) with CPSP was slightly longer than the control group (MFC-0), but MFC-C's maximum output voltage (648.4 mV) and power density (2738 mW/m3) could be increased by 5% and 15% higher than that of MFC-0 (P < 0.05). The degradation process of MFC substrate in unit cycle was mainly divided into nitrogen removal stage (0-8 h) and electricity generation stage (8-48 h). The NO3--N and COD degradation and power generation kinetic processes of MFC conformed to the Han-Levenspiel model. Kinetics experiments showed CPSP can improve the affinity and tolerance of MFC to NO3--N, also it can alleviate the pressure of electron competition in anolyte and improve coulombic efficiency. In addition, microbial communities were significantly changed under the effect of CPSP (P < 0.001). Meanwhile, CPSP can promote the synthesis of denitrification functional genes. This study provides a new strategy to improve the performance of MFC by the addition of novel denitrification carbon source.

Effects of antibiotics on corncob supported solid-phase denitrification: Denitrification and antibiotics removal performance, mechanism, and antibiotic resistance genes.

Solid-phase denitrification (SPD) has been used in wastewater treatment plant effluent to enhance nitrate removal, and antibiotics co-existing in the effluent is a common environmental problem. In this study, it was systematically investigated the effect of single trace sulfamethoxazole (SMX)/trimethoprim (TMP) and their mixture on microbial denitrification performance, the antibiotics removal, and antibiotics resistance genes (ARGs) in corncob supported SPD system. The average denitrification rate was improved by 46.90% or 61.09% with single 50 µg/L SMX or TMP, while there was no significant inhibition with mixed SMX and TMP. The abundance of dominant denitrifiers (Comamonadaceae family and Azospia) and fermentation bacteria (Ancalomicrobium) were consistent with the denitrification performance of different antibiotics groups. Single SMX and TMP achieved relatively higher denitrification gene and enzyme abundance. Mixed SMX and TMP improved the denitrification gene copies, but they reduced the key denitrification enzymes except for EC 1.7.7.2. Additionally, the removal efficiency of TMP (56.70% ± 3.18%) was higher than that of SMX (25.44% ± 2.62%) in single antibiotic group, and the existence of other antibiotics (i.e. SMX or TMP) had no significant impact on the TMP or SMX removal performance. Biodegradation was the main removal mechanism of SMX and TMP, while sludge and corncob adsorption contributed a little to their removal. SMX had the risk of sulfanilamide resistance genes (SRGs) dissemination. Furthermore, network analysis indicated that Niveibacterium and Bradyrhizobium were the potential hosts of SRGs, which promoted the horizontal transmission of ARGs.

Initial carbon release characteristics, mechanisms and denitrification performance of a novel slow release carbon source.

External carbon source addition is one of the effective methods for the treatment of wastewater with low carbon to nitrogen ratio (C/N). Compared with fast-release liquid carbon sources, slow-release solid carbon sources are more suitable for the denitrification process. A novel slow-release solid carbon source (corncob-polyvinyl alcohol sodium alginate- poly-caprolactone, i.e. CPSP) was prepared using corn cob (CC) and poly-caprolactone with polyvinyl alcohol sodium alginate as hybrid scaffold. The physical properties and carbon release characteristics of CPSP and three other carbon sources were compared. CPSP had stable framework and good carbon release performance, which followed the second order release equation. The formic acid, acetic acid, propionic acid and butyric acid released from CPSP accounted for 8.27% ± 1.66 %, 56.48% ± 3.71 %, 18.46% ± 2.69% and 16.79% ± 3.02% of the total released acids respectively. The start-up period of CPSP was shorter than that of the other carbon sources in denitrification experiment, and no COD pollution was observed in the start-up phase (25-72 h) and stable phase (73-240 hr). The composition and structure of the dissolved organic compounds released by CPSP and other carbon sources were analyzed by UV-Vis absorption spectroscopy and three-dimensional fluorescence spectroscopy, which indicated that CPSP was more suitable for denitrification than the other studied carbon sources.

Effects of rosmarinic acid on the inflammatory response in allergic rhinitis rat models after PM2.5 exposure.

BACKGROUND: Studies have shown the promising prospects of rosmarinic acid (RosA) for the prevention and treatment of allergic diseases. OBJECTIVE: The aim of this study was to investigate the effects of RosA on inflammatory reaction in rat models of allergic rhinitis (AR) after PM2.5 exposure. METHODS: Allergic rhinitis rat models were established by ovalbumin sensitization, and PM2.5 was applied at a concentration of 1000 µg/m3 , 3 h a day for 30 consecutive days. RosA was administered via intraperitoneal injection (20 mg/kg/d) for seven consecutive days. Allergic nasal symptoms were recorded. The expressions of interleukin (IL)-4, IL-13, interferon (INF)-γ, and OVA-sIgE were determined by ELISA. Histopathological changes in nasal mucosa were observed by HE staining. mRNA expressions of T-bet and GATA-3 in nasal mucosa were detected by RT-PCR. NF-κBp65 in cell nuclei and IκBα in cytoplasm were analyzed by Western blot. RESULTS: PM2.5 exposure worsened allergic nasal symptoms in AR rats, while RosA ameliorated these symptoms. Histopathologically, AR rats exhibited disorganized nasal mucosal epithelium, cell exfoliation, eosinophilic infiltration of lamina propria, gland swelling, and submucosal vascular congestion, which were aggravated by PM2.5 exposure and alleviated by RosA. RosA decreased the expressions of IL-4, IL-13, and increased the level of IFN-γ in PM2.5-exposed AR rats. After RosA intervention, the expressions of GATA-3 mRNA and NF-κBp65 in PM2.5-exposed AR rats were significantly reduced, while those of T-bet mRNA and IκBα were markedly increased. CONCLUSION: Rosmarinic acid may alleviate symptoms of AR rat models exposed to PM2.5 through the modulation of the NF-κB pathway and Th1/Th2 balance.

The Relationship Between Reading Strategy and Reading Comprehension: A Meta-Analysis.

This study synthesized the correlation between reading strategy and reading comprehension of four categories based on Weinstein and Mayer's reading strategy model. The current meta-analysis obtained 57 effect sizes that represented 21,548 readers, and all selected materials came from empirical studies published from 1998 to 2019. Results showed that reading strategies in all the four categories had a similar correlation effect size with reading comprehension. The correlation between monitoring strategy and reading comprehension was significantly larger in first language scripts than second language scripts. Affective strategy and elaboration strategy had an independent effect on reading comprehension, which was not significantly moderated by selected moderators. Results suggested that the reading strategies of all the four categories may have a similar contribution to text comprehension activities.

[Release Mechanisms of Carbon Source and Dissolved Organic Matter of Six Agricultural Wastes in the Initial Stage].

As carbon sources for the denitrification process, agricultural wastes have some problems, such as excess release of organic carbon; unclear release characteristics of nitrogen, phosphorus, and colorimetric substances; and unclear components, release mechanisms, and potential effects of the released dissolved organic matter (DOM) in the start-up period. To resolve those problems, rice straw, wheat straw, corn stalk, corncob, soybean stalk, and soybean hull were selected as denitrification carbon sources to investigate the release mechanisms and potential influences of the organic matter, secondary pollutants, and DOM. The results showed that the six agricultural wastes could be used as the denitrification carbon source. The carbon content in the wheat straw was the highest and the secondary pollution risk from the corncob was the lowest. For the six carbon sources, the second-order kinetic equation and Ritger-Peppas equation were followed during the 1-120 h carbon release process. The fitting results demonstrated that corncob was more suitable for use as the denitrification carbon source because of its moderate cm value and longer t1/2 value, and the release mechanisms of the six types of carbon sources were mainly controlled by the diffusion process. The NH4+-N, TN, and TP contents in the immersion water of the rice straw were higher than those of the five other agricultural wastes, and there was heavy chromaticity in the immersion water of the wheat straw and corn stalk. The amounts of nitrogen, phosphorus, and chromatic substances released from the corncob were the lowest. The leachates of the corncob and soybean hull had higher biodegradability and lower risks of secondary pollution than those of the other sources. The aromaticity and molecular weight of DOM increased as the reaction time increased, and the humification of DOM was low. Five components were identified by PARAFAC. The main component was protein-like matter, which was mainly composed of tyrosine-like and tryptophan-like substances. There was less humic acid-like matter in the immersion water. The component characteristics of DOM might have had an adverse effect on the subsequent water treatment process. These results could provide theoretical support for the impact on effluent water quality and risk assessment when the agricultural wastes are used as an additional denitrification carbon source at the start-up stage.

miR-338-3p inhibits autophagy in a rat model of allergic rhinitis after PM2.5 exposure through AKT/mTOR signaling by targeting UBE2Q1.

Exposure to fine particulate matter (PM2.5) increases the incidence of allergic rhinitis (AR). microRNA (miRNA) can regulate cell proliferation, invasion and apoptosis. However, the mechanism of miR-338-3p in mediating PM2.5-induced autophagy in AR animal models remains unknown. To explore the mechanism of miR-338-3p in PM2.5-induced autophagy in AR, the human nasal epithelium cells and AR model exposed to PM2.5 were deployed. The results showed that miR-338-3p was down-regulated in both nasal mucosa of PM2.5-exacerbated AR rat models and PM2.5-treated RPMI-2650 cells. Forced expression of miR-338-3p could inhibit autophagy in vitro. miR-338-3p specifically bound to UBE2Q1 3'-untranslated region (3' UTR) and negatively regulated its expression. Overexpression of UBE2Q1 attenuated the inhibitory effects of miR-338-3p on PM2.5-induced autophagy of RPMI-2650 cells through AKT/mTOR pathway. Moreover, our in vivo study found that after administration of agomiR-338-3p in AR rats model, the expression of autophagy-related proteins decreased and nasal symptoms alleviated. In conclusion, this study revealed that miR-338-3p acts as an autophagy suppressor in PM2.5-exacerbated AR by directly targeting UBE2Q1 and affecting AKT/mTOR pathway.

Release Mechanism, Secondary Pollutants and Denitrification Performance Comparison of Six Kinds of Agricultural Wastes as Solid Carbon Sources for Nitrate Removal.

Agricultural wastes used as denitrification carbon sources have some drawbacks such as excessive organic carbon release and unclear release characteristics of nitrogen, phosphorus, and chromatic substances, which can cause adverse effects on the effluent quality during the denitrification process. The composition and surface characteristics, carbon release mechanisms, and secondary pollutant release properties of six kinds of agricultural wastes, i.e., rice straw (RS), wheat straw (WS), corn stalk (CS), corncob (CC), soybean stalk (SS), and soybean hull (SH) were studied and analyzed in this research. The denitrification performance of these agricultural wastes was also investigated extensively by batch experiments. The results showed that the carbon release basically followed the second-order reaction kinetic equation and Ritger-Peppas equation in the 120 h reaction, and it was mainly controlled by the diffusion process. The kinetic equation fitting results and bioavailability test suggested that the potential risk of excessive effluent COD of CC was the lowest due to the appropriate amount and degradability of its released carbon. The NH4+-N, TN, and TP in the leachate of RS were higher than those of the other five agriculture wastes, and the chroma in the leachate of WS and CS was heavier than that of the others. CC released the lowest pollutants, which resulted in slight fluctuations of effluent quality in the start-up period (1-11 d), and it had the best nitrogen removal capacity in the denitrification experiment. The average NO3--N removal of CC was 5.12 mg for each batch in the stable period (11-27 d), which was higher than that of others, and less NO2--N, NH4+-N, and COD were accumulated in the CC effluent during the whole denitrification process.

Distribution characteristics of nitrogen and the related microbial community in the surface sediments of the Songhua River.

Nitrogen in surface sediments is becoming an ecological risk to the river environment and it is essential to clarify the relationship between the different forms of nitrogen and related microorganisms. A survey was conducted to analyze the distribution characteristics of the nitrogen and related microbial community in the sediments of the Songhua River during normal season and dry season. In the surface sediments of the Songhua River, no total nitrogen (TN) pollution risk was observed according to the U.S. EPA assessment criteria (1000 mg kg-1) for sediment contamination, but TN in several sampling sites (554.9-759.7 mg kg-1) exceeded the alert values (550 mg kg-1) should be concerned according to the guidelines issued by the Ministry of Environment and Energy of Ontario, Canada. The average TN, NH4 +-N, NO3 --N and total organic nitrogen (TON) in the surface sediments of the Songhua River during normal season were higher than those in the dry period. TON was the main form of nitrogen in the sediment of Songhua River, NO2 --N content was lowest and no obvious difference was observed between normal and dry seasons. The highest average NH4 +-N of both seasons occurred in the Nenjiang River, and the highest average NO3 --N of both seasons were found in the main stream of the Songhua River. The community abundance of AOB genes (1.1 × 107 to 2.5 × 108 copies per g soil in normal season, 7.2 × 105 to 3.3 × 108 copies per g soil in dry season) was higher than that (1.2 × 106 to 9.7 × 107 copies per g soil in normal season, 6.6 × 104 to 3.2 × 107 copies per g soil in dry season) of AOA genes in both normal and dry seasons. The denitrifying nirS genes were predominant in both seasons, and their abundance (1.8 × 106 to 8.0 × 108 copies per g soil) in dry season was higher than that (9.7 × 105 to 4.6 × 108 copies per g soil) in normal season. Moreover, the moisture concentration, pH, dissolved oxygen and different formation of nitrogen were key factors affecting the variation of nitrogen-transformation microorganisms during normal and dry seasons. This research could help to explain the relationship between nitrogen transformation and the related microbial community in the surface sediment, which could provide a scientific basis for water ecological restoration and water environment improvement of Songhua River.

Effectiveness of Metacognitive Regulation Intervention on Attention-Deficit-Hyperactivity Disorder Students' Scientific Ability and Motivation.

This study investigated the effect of metacognitive regulation (McR) intervention on attention-deficit-hyperactivity disorder (ADHD) students' astronomy knowledge acquisition and learning motivation. Through a cognitive-behavioural treatment design, this study selected 97 ADHD learners who had poor academic performance. This study divided ADHD students randomly into one experimental group and one control group. After 15 weeks of intervention, results showed that the experimental group students performed significantly better than the control group in scientific abilities, learning motivation, and metacognition. Results suggested that the McR intervention is an effective approach for improving the ADHD students' science knowledge learning abilities.

Ursolic Acid Alleviates Mucus Secretion and Tissue Remodeling in Rat Model of Allergic Rhinitis After PM2.5 Exposure.

BACKGROUND: According to recent epidemiologic studies, exposure to fine particulate matter (particulate matter 2.5 ≤ µm [PM2.5]) in the air increases the incidence and severity of allergic rhinitis (AR). Ursolic acid (UA) has activities in immune regulation and anti-inflammatory. However, the role of UA intervention on PM2.5-exposed AR remains unknown. In this study, we investigated the effects of UA on tissue remodeling and mucus hypersecretion in a rat model of AR after PM2.5 exposure. METHODS: AR was induced in rats with ovalbumin (OVA) and they were exposed to ambient PM2.5(200 µg/m3) via a PM2.5 inhalation exposure system for 30 days(ARE group). Ursolic acid intervention was administrated in the AR model after PM2.5 exposure (UA group). Hyperplasia of goblet cells was detected by periodic acid-Schiff (PAS) staining and collagen deposition in the nasal mucosa was detected by Masson trichrome (MT) staining.MUC5AC expression was measured by immunohistochemistry. RESULTS: UA group showed reduced goblet cell hyperplasia and collagen deposition in the nasal mucosa which exacerbated after PM2.5 exposure, as reflected by PAS and MT staining when compared with the ARE group. Immunohistochemical results showed that the expression of MUC5AC in the UA group was lower than that in the ARE group. CONCLUSION: Analysis of our data indicated that UA could attenuate nasal remodeling and mucus hypersecretion in aggravation of AR after PM2.5 exposure, which may be the pathophysiologic mechanisms for the prevention of AR exacerbated by exposure to PM2.5.

Contribution of Vocabulary Knowledge to Reading Comprehension Among Chinese Students: A Meta-Analysis.

This study investigated the correlation between vocabulary knowledge and reading comprehension. To address the correlation picture under Chinese logographical scripts, the researchers investigated the potential explanation for the correlation via Reading Stage, Information Gap, Content-based Approach, and Cognition and Creativity Theory approaches. This study undertook a meta-analysis to synthesize 89 independent samples from primary school stage to Master's degree stage. Results showed the correlation picture as an inverted U-shape, supporting the idea that vocabulary knowledge contributed a large proportion of variance on text comprehension and might also support the independent hypothesis of the impact of vocabulary knowledge on reading comprehension. In each education stage, the correlation between vocabulary knowledge and reading comprehension was independent in that it did not interact with any significant moderators. This study informed that the vocabulary knowledge not only determined text comprehension progress through facial semantic meaning identification but also suggested that the coordinate development of vocabulary knowledge, grammatical knowledge, and inference would be better in complexity comprehension task performance.

Effects of N-acetylcysteine on oxidative stress and inflammation reactions in a rat model of allergic rhinitis after PM2.5 exposure.

Particulate matter 2.5 (PM2.5) exposure can increase the prevalence of allergic rhinitis (AR), the mechanism underlying which may include oxidative stress and inflammatory response. As a ROS quenching agent, N-acetylcysteine (NAC) can attenuate the accumulation of inflammatory cells and hyper-responsiveness in animal asthma models. To explore the effect of NAC on the oxidative stress and inflammatory reactions in AR rats exposed to PM2.5, we analyzed the components of PM2.5 and examined the nasal symptoms, redox level in nasal mucosa, Th1/Th2-related serum cytokines, nasal mucosal histopathology and ultrastructure in AR rat models with NAC intervention after PM2.5 exposure. The results showed that the high concentrations of metal cations and PAHs in PM2.5 could aggravate Th2-dominant allergic inflammation in AR model and cause redox imbalance, accompanied by nasal epithelial cell stripping and eosinophil infiltration, while NAC intervention could alleviate the clinical symptoms of AR model after PM2.5 exposure, correct the redox imbalance, reduce the Th2 cytokines, reduce eosinophil infiltration, and promote the moderate regeneration of epithelial cells. The mechanism of NAC reversing PM2.5-mediated action may be related to its anti-oxidant and anti-inflammatory effects, which may provide some new insights for the prevention of AR exacerbated by exposure to PM2.5.

[Nitrogen Removal in Low-C/N Rural Sewage Treatment by Anoxic/Oxic Biofilter Packed with New Types of Fillers].

When low-concentration rural sewage is treated biologically, the effluent total nitrogen (TN) concentration often does not meet the discharge limit because of its low carbon-to-nitrogen ratio (C/N). To solve this problem, a laboratory-scale anoxic/oxic (A/O) biofilter packed with Arundo donax and activated carbon as the anoxic and aerobic column fillers (No. 2) was operated for treatment of simulated rural sewage and advanced nitrogen removal, while an ordinary gravel-packing A/O biofilter (No. 1) was set up as the control group. The results were as follows. When the influent chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), and TN concentrations were (79.47±14.21), (34.49±2.08), and (34.73±3.87) mg·L-1, respectively, the No. 1 and No. 2 reactors achieved removal efficiencies of (88.00±7.00)% and (89.00±10.00)%, (90.00±2.00)% and (97.00±7.00)%, and (37±15)% and (68±7)%, respectively. The results revealed that using Arundo donax and activated carbon new fillers could significantly enhance NH4+-N and TN removal. High-throughput sequencing results indicated that the microorganisms involved in the nitrification process in the No. 1 reactor mainly belong to Proteobacteria, whereas those in the No. 2 reactor belong to Proteobacteria and Nitrospirae. In addition, the main denitrification bacterial phyla in the anoxic column of the No. 1 reactor were Chloroflexi, Proteobacteria, Bacteroidetes, and Planctomycetes, whereas those in the anoxic column of the No. 2 reactor were primarily Bacteroidetes, Proteobacteria, Firmicutes, and Patescibacteria. Quantitative real time polymerase chain reaction (qPCR) results showed that the microbial nitrification (amoA and Nitrospira 16S rDNA), denitrification (narG, nosZ, nirS, and nirK), and anaerobic ammonium oxidation functional genes (ANAMMOX) in the No. 2 reactor were significantly higher than those in the No. 1 reactor. All the genes, except for the narG and nosZ genes, had one to two orders of magnitude of improvement in the No. 2 reactor compared to those in the No. 1 reactor.

Longitudinal Effects of Mediums of Word Explanation on L2 Vocabulary Learning Strategies Among Chinese Grade-7 Students.

This longitudinal study investigated how different mediums of word explanation affected the use of English vocabulary strategies among Chinese Grade-7 students. 170 students were tested on their English receptive vocabulary size and vocabulary strategy application before and after an 8.33-month intervention. Students were divided into three experimental groups and one control group. The three experimental groups were provided with learning materials that explained the target vocabulary in three mediums, respectively: English-only, English-and-Chinese, and Chinese-only. Results showed that, after the intervention, receptive vocabulary size did not have any direct significant impact on vocabulary strategy development, whereas mediums of word explanation materials impacted students' application of vocabulary learning strategies (VLS) in different ways. Our findings showed that the English-only mediums significantly enhanced students' use of metacognition, cognition, and memorization strategies, but decreased social strategy development. Chinese-only mediums significantly facilitated cognition and memorization strategy development. Implications for L2 vocabulary education are discussed.

Comparative Study of Denitrifying-MBBRs with Different Polyethylene Carriers for Advanced Nitrogen Removal of Real Reverse Osmosis Concentrate.

Nitrogen (N) remains a great challenge in wastewater treatment while attempts to remove N has continuously been a research point for decades. In this study, the long-term performance of four identical-shape denitrification MBBRs (moving bed biofilm reactors) with four different configurations of cylindrical polyethylene as carriers (Φ25 × 12, Φ25 × 4, Φ15 × 15, and Φ10 × 7 mm) for advanced N removal of real reverse osmosis concentrate was investigated in great detail. The N of the real concentrate can be effectively removed by denitrification MBBRs when the pH, temperature, hydraulic retention time (HRT), C/N ratio, and filling rate are 7.50-8.10, 24~26 °C, 12 hours, 6.6, and 50%, respectively. The results showed that the MBBR with the Φ15 × 15 poly-carrier had the best removal efficiency on NO3--N (78.0 ± 15.8%), NO2--N (43.79 ± 9.30%), NH4+-N (55.56 ± 22.28%), and TN (68.9 ± 12.4%). The highest biomass of 2.13 mg/g-carrier was in the Φ15 × 15 poly-carrier was compared with the other three carriers, while the genes of the Φ15 × 15 poly-carrier reactor were also the most abundant. Proteobacteria was the most abundant phylum in the system followed by Bacteroidetes and then Firmicutes. The entire experiment with various parameter examination supported that Φ15 × 15 poly-carrier MBBR was a promising system for N removal in high strength concentrate. Despite the lab-scale trial, the successful treatment of high strength real reverse osmosis concentrate demonstrated the reality of the treated effluent as possible reclaimed water, thus providing a good showcase of N-rich reverse osmosis concentrate purification in practical application.

Effects of Ursolic Acid on the Expression of Th1-Th2-related Cytokines in a Rat Model of Allergic Rhinitis After PM2.5 Exposure.

BACKGROUND: Allergic rhinitis (AR) is a global health problem and closely related to environmental factors. Ursolic acid (UA) has potential in the treatment of allergic inflammation. The effects of UA intervention on PM2.5-induced AR remain uncertain. OBJECTIVE: To assess the effects of UA on nasal symptoms and the expression of T-helper (Th)1-Th2-related cytokines in a rat model of AR after fine particulate matter (particulate matter ≤ 2.5 µm [PM2.5]) exposure. METHODS: A total of 40 healthy female Sprague-Dawley rats were randomly divided into 4 groups: normal control group (NC group), ovalbumin (OVA)- induced AR model (AR group), PM2.5-exposed AR group exposed to 200 g/m3 PM2.5 for 30 days via inhalation (ARE group), and a group with UA intervention to the AR model after PM2.5 exposure (UA group). UA intervention was adopted after PM2.5 exposure in the UA group. Nasal symptoms and levels of Th1-Th2 cytokines in the serum were detected in each individual rat. The pathological changes and expression of Eotaxin in the nasal mucosa of each individual rat were examined by histology. RESULTS: PM2.5 significantly increased the number of sneezes and nasal rubs in the rats with AR, and UA alleviated these symptoms. UA decreased interleukin (IL)-4, IL-5, IL-13, Eotaxin-1, and OVA Immunoglobulin E (IgE) protein levels. In the AR group, hematoxylin and eosin staining showed disordered arrangement of the nasal mucosa epithelium, cell shedding, eosinophilic infiltration, swelling of the glands, and submucosal vascular congestion. UA group showed reduced eosinophilic infiltration and orderly arrangement of the mucosal epithelium when compared with the ARE group. Immunohistochemical results showed that the expression of Eotaxin in the UA group was lower than that in the ARE group. CONCLUSION: UA could relieve nasal symptoms caused by PM2.5 exposure, the possible mechanism of which is to inhibit the expression of Th2 cytokines, eosinophilic infiltration, and specific IgE production.

Effect of PM2.5 on MicroRNA Expression and Function in Nasal Mucosa of Rats With Allergic Rhinitis.

BACKGROUND: Particulate matter 2.5 (PM2.5) refers to particulate matter with aerodynamic equivalent diameter less than or equal to 2.5 µm, which is an important component of air pollution. PM2.5 aggravates allergic rhinitis (AR) and promotes AR nasal mucosa inflammation. Therefore, the influence of PM2.5 inhalation exposure on microRNA (miRNA) expression profiles and function in the nasal mucosa of AR rats was investigated. METHODS: Female Sprague Dawley rats were distributed randomly to 2 groups: AR model PM2.5 exposure group (ARE group) and AR model PM2.5-unexposed control group (ARC group). The rats of ARE group were made to inhale PM2.5 at a concentration of 200 µg/m3, 3 h/day, for 30 days. miRNA expression profiles of the nasal mucosa from both groups were determined using an miRNA gene chip and were verified by quantitative real-time PCR (qRT-PCR). Gene function enrichment analysis was performed using bioinformatics analysis. RESULTS: The ARE group revealed 20 significantly differentially expressed miRNAs, including 4 upregulated and 16 downregulated miRNAs (fold change > 1.5 or < 0.66, P < .05). Of these, 9 selected miRNAs were verified by qRT-PCR, and the results of 8 miRNAs were in accordance with the miRNA gene chip results, with highly positive correlation (r = .8583, P = .0031). Numerous target genes of differentially expressed miRNAs were functionally enriched in high-affinity immunoglobulin E receptor signaling, ErbB signaling, mucin O-glycans biosynthesis, transforming growth factor ß signaling, mitogen-activated protein kinase signal transduction, phosphatidylinositol signaling, mucopolysaccharide biosynthesis, mammalian target of rapamycin signaling, T cell receptor signaling, Wnt signaling, chemokine signal transduction, and natural killer cell-mediated cytotoxicity pathways. CONCLUSIONS: PM2.5 causes significant changes in miRNA expression in the nasal mucosa of AR rats. miRNA plays an important role in regulating PM2.5 effects in AR rat biological behavior and mucosal inflammation. This study provides a theoretical basis for the prevention and treatment of AR from the effects of environmental pollution on the gene regulation mechanism.