Cocrystal of {Ti4} and {Ti6} Clusters with Enhanced Photochemical Properties.

Herein we report the construction of a supramolecular cocrystal {Ti4 + Ti6} through the combination of isolated {Ti4} and {Ti6} clusters. Moreover, the combined {Ti4 + Ti6} complex presents better solar-driven photocatalytic dye degradation activity than the individual {Ti4} and {Ti6} compounds.

Erratum: Amarogentin secoiridoid inhibits in vivo cancer cell growth in xenograft mice model and induces apoptosis in human gastric cancer cells (SNU-16) through G2/M cell cycle arrest and PI3K/Akt signalling pathway.

In the version of this article initially published, in Volume 21, issue 3, the first affiliation (affiliation number 1) was incorrectly stated as "Department of Pathology, Faculty of Medicine, Adnan Menderes University, Aydin, Turkey". The correct affiliation is "Department of Oncology, Shaoxing People's Hospital ,Shaoxing Hospital of Zhejiang University, Shaoxing 312000,China'. This error appeared only in the PubMed database and not in the print form of the Journal.

Amarogentin secoiridoid inhibits in vivo cancer cell growth in xenograft mice model and induces apoptosis in human gastric cancer cells (SNU-16) through G2/M cell cycle arrest and PI3K/Akt signalling pathway.

PURPOSE: To investigate the in vitro and in vivo antitumor effects of amarogentin in SNU-16 human gastric cancer cells as well as in nude mice xenograft model. The effects of this compound on cell apoptosis, cell cycle phase distribution and PI3K/Akt and m-TOR signalling pathways were also studied in detail. METHODS: MTT assay was used to study the effect of amarogentin on SNU-16 cell viability while clonogenic assay indicated the effect of the compound on colony formation tendency of these cells. Phase contrast microscopy revealed the effect on cellular morphology while flow cytometry was engaged to study the effects on cell apoptosis and cell cycle arrest. SNU-16 cancer cells were subcutaneously inoculated into nude mice to investigate the in vivo antitumor effects of amarogentin. RESULTS: Amarogentin induced potent, dose-dependent as well as time-dependent cytotoxic effects on the growth of SNU-16 human gastric cancer cells. Amarogentin also inhibited the colony forming capability of these tumor cells and its treatment led to morphological alterations in these cells in which the cells became withered and rounded, detached from one another and adopted irregular shapes while floating freely in the culture medium. In comparison to untreated control cells, the amarogentin treated cells with 10, 50 and 75 µM exhibited 32.5, 45.2 and 57.1 % apoptotic cells, respectively. Amarogentin induced potent and dose-dependent G2/M cell cycle arrest in these cells and led to downregulation of m-TOR, p-PI3K, PI3K, p-Akt and Akt and upregulation of cyclin D1 and cyclin E protein expressions. The tumor tissues obtained from the amarogentin-treated mice were much smaller than the tumor tissues derived from the control group. CONCLUSION: Amarogentin exerts potent in vitro and in vivo antitumor effects in SNU-16 cell model as well as in nude mice xenograft model. These antitumor effects were found to be mediated through apoptosis induction, G2/M cell cycle arrest and downregulation of PI3K/Akt/m-TOR signalling pathways.

[Concurrent chemoradiotherapy for locally advanced unresectable extrahepatic cholangiocarcinoma: a report of 19 cases].

OBJECTIVE: To evaluate the efficacy and toxicity of concurrent chemoradiotherapy for patients with locally advanced unresectable extrahepatic cholangiocarcinoma. METHODS: Thirty-eight patients with locally advanced unresectable extrahepatic cholangiocarcinoma admitted in Shaoxing People's Hospital from February 2007 to February 2012 were enrolled in the study. They were randomized into sequential chemoradiotherapy (n=19) or concurrent chemoradiotherapy group (n=19). All patients were treated with intensity modulated radiation therapy (IMRT). Patients in concurrent chemoradiotherapy group received the regimen of gemcitabine plus oxaliplatin. Tumor response and adverse effects were observed periodically. The primary end points were disease progression-free survival (PFS) and overall survival (OS). RESULTS: The response rates of sequential chemoradiotherapy and concurrent chemoradiotherapy groups were 42.1% (8/19) and 63.2% (12/19). The disease control rates of them were 78.9% (15/19) and 84.2% (16/19))， respectively. The median PFS of sequential chemoradiotherapy group and concurrent chemoradiotherapy group was 8.3 (95%CI: 7.6-9.0) and 10.4 months (95%CI: 9.4-11.4, P=0.037), and the median OS in two groups were 14.2 (95%CI: 12.6-15.8) and 15.6 months (95%CI: 14.2-17.0, P=0.095), respectively. The major adverse reactions were controllable hematology toxicity and gastrointestinal reaction. There was no significant difference in incidence of adverse reactions between two groups (P>0.05). CONCLUSION: Sequential chemoradiotherapy and concurrent chemoradiotherapy may improve PFS and OS in patients with locally advanced unresectable extrahepatic cholangiocarcinoma, and both are well-tolerated. In addition, concurrent chemoradiotherapy might provide additional PFS benefit and would be preferable.

[Rapid Start-up of Continuous Autotrophic Nitrogen Removal Reactor by Hybrid-inoculating PN and PN/A Granular Sludges].

The rapid cultivation of partial nitritation/ANAMMOX （PN/A） granular sludge in a continuous-flow mode is one of the key technologies for efficient biological nitrogen removal in domestic wastewater treatment. Compared with that in PN/A granular sludge, PN granular sludge demonstrates a shorter incubation period and suitability for batch culture. It is also a good carrier for enriching ANAMMOX （AMX） bacteria. In this study, we established a continuous-flow autotrophic nitrogen removal process in three continuously stirred tank reactors （CSTR） （R1-R3） by hybrid-inoculating PN/A and PN granular sludge at the mass ratios of 3∶1, 1∶1, and 1∶3, respectively. By implementing high ammonium nitrogen loading and short hydraulic retention time, continuous autotrophic nitrogen removal processes were successfully started up in the three CSTRs. The results showed that compared with that of R1 and R2, R3 had a longer start-up time but a similar steady-state nitrogen removal performance. The total nitrogen removal load of R3 could be more than 2.6 kg·ï¼ˆm3·d）-1. Intriguingly, the inoculated PN granular sludge served as a precursor for PN/A granular sludge cultivation. This approach facilitated the enrichment of anaerobic ammonia-oxidizing bacteria （AMX） by introducing abundant ammonium-oxidizing bacteria （AOB） and nitrite nitrogen substrates into the CSTR. According to the results of high-throughput sequencing, the microbial abundance and diversity of the mature granules in R1-R3 were significantly higher than those of the inoculation sludge. AOB （genus Nitrosomonas）, AMX （genera Candidatus Kuenenia and Candidatus Brocadia）, and symbiotic heterotrophs, such as Chloroflexi, Bacteroidetes, and Chlorobi, drove the autotrophic nitrogen removal process and maintained the stability of the granular structure. In summary, a novel start-up strategy of hybrid-inoculating granular sludge was provided for a continuous-flow autotrophic nitrogen removal in engineering application.

Investigating the effects of herbaceous root systems on the soil detachment process at the species level.

Plant root growth significantly affect soil detachment process, whereas the mechanism of how roots affect the soil detachment process by overland flow at species level is not fully understood. This study was conducted to investigate the soil detachment rate responds to plant-induce soil properties and root traits at species level. Two typical herbaceous plants, Bothriochloa ischcemum (Linn.). Keng (BI; fibrous root system) and Artemisia vestita Wall. ex Bess (AG; tap root system), from the Loess Plateau were studies for one year under six planted densities of 5 plants m-2, 10 plants m-2, 15 plants m-2, 20 plants m-2, 25 plants m-2, and 30 plants m-2. In total, 24 steel tanks were planted, and two plots were used as bare soil controls. Their soil detachment rates were tested under a constant overland flow (1.5 l s-1) on a 26.2 % slope. The results showed that soil detachment rate under the six planted densities ranged from 0.034 kg m2 s-1 to 0.112 kg m2 s-1 for BI and was ranged from 0.053 kg m2 s-1 to 0.132 kg m2 s-1 for AG, which all greatly reduced soil detachment rate and were 68.17 % to 92.33 % and 69.20 % to 87.27 % less than that of the control. In general, BI was more effective in reducing soil detachment rate than AG, achieving a mean soil detachment rate that was 23.75 % lower. With increasing plant density, soil detachment rate decreased as a power function. The overland flow hydraulic characteristics, soil properties and root traits influenced by plant density were positively or negatively correlated with soil detachment rate. Specifically, soil detachment rate decreased with velocity, bulk density, root length density, and increased with shear stress and Darcy-Weisbach friction factor as power or exponential functions. On this basis, the soil detachment rate (Dr) can be satisfactorily estimated by overland flow velocity (v), soil bulk density (BD) and root length density (RLD) as a power function (Dr = 63.03v0.174 × BD-20.712 × RLD-0.233R2 = 0.65; NSE = 0.60; p < 0.01).

Efficacy and safety of pembrolizumab monotherapy in EGFR-mutant squamous cell lung cancer with PD-L1 over-expression: A case report.

BACKGROUND: Epidermal growth factor receptor (EGFR)-mutant nonsmall cell lung cancer (NSCLC) patients are less likely to be programmed death-ligand 1 (PD-L1)-positive compared with wild-type EGFR mutant tumors. Given the rarity of actionable driver genes in squamous cell lung cancer (SQCC), the frequency of SQCC patients simultaneously carrying EGFR driver gene mutation and having PD-L1 over-expression is extremely low. Studies on the effectiveness and safety of EGFR-TKIs or immune-checkpoint inhibitors (ICIs) in this subset of patients are lacking. PATIENT CONCERNS: The patient suffered from coughing and chest pain for 1 month. A chest CT revealed a mass with a cavity in the right lung, enlarged mediastinal lymph nodes, diffuse pleural thickening in the right pleura, and pleural effusion of the right chest. DIAGNOSIS: A pleural biopsy was performed using a video-assisted thoracoscope. The pathological examination revealed a poorly differentiated squamous cell carcinoma of lung. Further genetic testing identified exon 19 deletion mutation in EGFR with abundance of 0.27%. Meanwhile, immunohistochemical PD-L1 analysis showed a TPS of 90%. INTERVENTIONS: The patient was initially resistant to EGFR-TKIs but exhibited a rapid and marked response to pembrolizumab. OUTCOMES: After 5 cycles of pembrolizumab monotherapy, the patient developed Grade 3 immune-related dermatitis, and ICI therapy was suspended. CONCLUSIONS: ICI monotherapy could be an effective therapy in SQCC patients with low-abundance of EGFR mutations and PD-L1 over-expression. However, close attention should be paid to immune-related adverse events.

CREB1 promotes proliferation and differentiation by mediating the transcription of CCNA2 and MYOG in bovine myoblasts.

The cAMP response element binding protein 1 (CREB1) is an important nuclear transcription factor in eukaryotes. To explore the potential role of CREB1 on Qinchuan bovine skeletal myoblasts, we investigated the function of CREB1 on proliferation and differentiation. In this study, we found that CREB1 promoted cell proliferation by promoting DNA synthesis in S phase and cell division in G2 phase and promoted myogenic differentiation process in bovine myoblasts. Through dual luciferase experiments, we found that CREB1 can bind to the proximal promoter regions of CCNA2 and MyoG, indicating that CREB1 can play a positive regulatory role in the proliferation and differentiation of myoblasts by mediating the transcription of CCNA2 and MyoG. In addition, through downstream target gene analysis and transcriptome sequencing, we found that CREB1 plays a role in cell proliferation, myogenic differentiation, skeletal muscle repair and other related pathways.

[Effects of Cold Acclimation on the Activity of Autotrophic Nitrogen Removal in Granular Sludge and Its Bacterial Population Structure].

Cold acclimation is an effective approach for improving the nitrogen removal performance and operational stability of partial nitritation/ANAMMOX (PN/A) combined processes at low temperatures. To explore the specific effects of cold acclimation on the characteristics of sludge, differentiations in temperature sensitivity, granular morphology, composition of extracellular polymer substance (EPS), and bacterial community structure between PN/A granular sludges cultivated at medium-high temperature (30℃) and acclimated to low temperature (15℃) were investigated in this study. The results of reaction thermodynamics showed that the nitrogen removal performance of the granules acclimated to low temperature (GL) was significantly higher than that of those cultivated at medium-high temperature (GH) under the low temperature (10-20℃), and the apparent activation energy (Ea) of total inorganic nitrogen removal for the former was decreased by 28.4%. Compared with GH, GL had a smaller average particle size of 25.8% and higher EPS contents of 16.6%, resulting in a significant lower settling property. Based on the high-throughput sequencing results, GL exhibited a higher diversity of bacterial community, and a lower relative abundance ratio (0.04) of aerobic ammonium-oxidizing bacteria (Nitrosomonas) and anaerobic ammonium-oxidizing bacteria (Candidatus_Kuenenia) than 0.34 for GH. It indicated that the PN/A granules held a strong ability to retain slow-growing autotrophic bacteria in the system, even under low temperatures. These findings could provide meaningful references for analyzing the self-adaption mechanisms of PN/A sludge to low temperature conditions and promote the industrial application of combined processes.

Amarogentin secoiridoid inhibits in vivo cancer cell growth in xenograft mice model and induces apoptosis in human gastric cancer cells (SNU-16) through the mediation of G2/M cell cycle arrest and PI3K/Akt signalling pathway.

The Editors of JBUON issue an Expression of Concern to 'Amarogentin secoiridoid inhibits in vivo cancer cell growth in xenograft mice model and induces apoptosis in human gastric cancer cells (SNU-16) through G2/M cell cycle arrest and PI3K/Akt signalling pathway', by Jian-Guo Zhao, Ling Zhang, Xiao-Jun Xiang, Feng Yu, Wan-li Ye, Dong-Ping Wu, Jian-Fang Wang, Jian-Ping Xiong, JBUON 2016;21(3):609-617; PMID:27569081. Following the publication of the above article, readers drew to our attention that part of the data was possibly unreliable. We sent emails to the authors with a request to provide the raw data to prove the originality, but received no reply. Therefore, as we continue to work through the issues raised, we advise readers to interpret the information presented in the article with due caution. We thank the readers for bringing this matter to our attention. We apologize for any inconvenience it may cause.

Clinical efficacy of Qi Di laxative decoction in the treatment of functional constipation: A protocol for systematic review and meta-analysis.

BACKGROUND: Functional constipation (FC) is a common gastrointestinal disorder characterized by slow bowel movement and defecation difficulties, significantly impacting patients' quality of life and exerting heavy financial burden to whole society. However, more than 50% FC patients are not completely satisfied with current therapies and alternative therapies are urgently required. Increasing evidences have demonstrated that traditional Chinese medicine has a good therapeutic effect on FC, which is well known for its multitarget and multimode effects on diverse diseases as well as less side effects. Furthermore, studies proved that Qi Di Laxative Decoction was an effective treatment for FC. Its safety and effectiveness should be verified by further studies. METHODS: We will search the following electronic databases for randomized controlled trials to evaluate the clinical efficacy of Qi Di Laxative Decoction in treating FC: Wanfang and Pubmed Database, China National Knowledge Infrastructure Database, Cochrane Central Register of Controlled Trials, Cumulative Index of Nursing and Allied Health Literature, and Excerpta Medica database. Each database will be searched from inception to November 2020. The entire process will include study selection, data extraction, risk of bias assessment, and meta-analyses. RESULTS: This proposed study will evaluate the clinical efficacy of Qi Di Laxative Decoction for patients with FC. The outcomes will include changes in FC relief and adverse effect. CONCLUSION: This proposed systematic review will evaluate the existing evidence on the clinical efficacy of Qi Di Laxative Decoction in treating FC. DISSEMINATION AND ETHICS: The results of this review will be disseminated through peer-reviewed publication. Because all of the data used in this systematic review and meta-analysis has been published, this review does not require ethical approval. Furthermore, all data will be analyzed anonymously during the review process. OSF REGISTRATION NUMBER: DOI 10.17605/OSF.IO/M2ESR.

[Rapid Achievement of Nitrifying Micro-granular Sludge and Its Nitritation Function].

The rapid achievement of nitrifying micro-granular sludge and its nitritation function was studied in a continuously operated internal-loop airlift reactor seeding with floccular sludge. Results showed that the sludge micro-granulation was almost realized within three weeks by gradually reducing the hydraulic retention time from 5 h to 2.5 h. The color of the sludge first changed from yellowish-brown to creamy white, and then changed to pale yellow during the micro-granulation process. The settleability of the sludge first changed from good to bad, and then recovered to good. The value of the sludge settling velocity (SV) at SV5 and SV30 were both equal to 4%-5%, while SVI30 and SVI5 were both around 12-13 mL·g-1. The average size of the obtained nitrifying micro-granular sludge was 134 µm on day 27. Nearly 70% of the nitrifying micro-granular sludge was maintained in a relatively narrow range of 59-163 µm, thus indicating the largely homogeneous diameter distribution of these micro-granules. After sludge micro-granulation, the nitritation function was achieved within one week by progressively increasing the influent NH4 concentrations from 50 mg·L-1to 200 mg·L-1. The NO2- accumulation ratio and the nitritation loading rate reached up to 90% and 1.34 kg·(m3·d)-1, respectively. The high level of residual NH4 concentration in the effluent, or the low ratio of dissolved oxygen (DO) to NH4+-N concentrations (0.03-0.09), should be the primary cause of the rapid achievement of nitritation in the micro-granular sludge reactor.

[Adaptability of Completely Autotrophic Nitrogen Removal over Granular Sludge to Low-Strength at Low Temperature].

A single-stage PN-ANAMMOX (PN/A) granular sludge cultured at room temperature was used to investigate the completely autotrophic nitrogen removal efficiency and microbial community structure of low-strength wastewater based on the completely autotrophic nitrogen removal over nitrite in granular sludge at a low temperature. The results showed that at the low temperature (15±1)℃, the ammonia nitrogen load was maintained at 1.29 kg ·(m3 ·d)-1, and the ammonia nitrogen concentration in the injection was gradually reduced from 70 mg ·L-1 to 40 mg ·L-1. DO/TAN was controlled at 0.22-0.25. The total nitrogen removal rate was maintained at (85±4)%, and the average TN concentration in the effluent was 8.9 mg ·L-1. There was no significant proliferation of nitrite-oxidizing bacteria (NOB) during the operation period, and the Nitrospira abundance was less than 1%. Elutriation of the floc sludge and the control of low DO/TAN values can be used as effective control strategies to inhibit NOB proliferation. Through completely autotrophic nitrogen removal over nitrite in granular sludge operated under low-temperature and low-substrate conditions, the particle size became smaller, and the color changed from brown red to brown yellow. The total amount of PS decreased slightly, and the ratio of PN/PS stabilized at 2.5-3.0. Planctomycetes and Proteobacteria dominated the community, and Candidatus_Kuenenia and Candidatus_Brocadia were two AMX bacteria in the sludge.

[Analysis of Rapid Start-up and Mixed Nutritional Nitrogen Removal Performance of Complete Autotrophic Granular Sludge].

A rapid start of the completely autotrophic nitrogen removal over nitrite (CANON) process based on granular sludge and efficient nitrogen removal under mixotrophic conditions are important steps in a continuous flow reactor for CANON engineering applications. In this study, an aged CANON granular sludge was mechanically crushed to 0.3 mm as inoculum in an airlift internal-loop reactor (AIR) to achieve simultaneous COD removal and mixotrophic denitrification of the single-stage granular sludge. The system achieved stable partial nitrification by controlling DO after 26 days of startup. Granulation and anaerobic ammonia oxidation were then promoted by shortening the HRT to increase the ammonia nitrogen load to 5.65 kg ·(m3 ·d)-1. The total nitrogen removal rate reached 58% on the 68th day. Subsequently, the C/N ratio of influent was increased from 0 to 0.25 and 0.5, which promoted the synergistic growth of AOB, AMX, and heterotrophic microorganisms. The removal rates of ammonia and total nitrogen were 95% and 85% respectively, and the removal of COD reached approximately 80%. The activity of NOB such as Nitrospira was effectively inhibited as the COD concentration was increased. q(NH4+-N) and q(TN) were stable at 0.4 g ·(g ·h)-1 and 0.34 g ·(g ·h)-1, respectively, while q(NO3--N) was approximately 0.02 g ·(g ·h)-1. Microbial diversity was observed using MiSeq high-throughput sequencing. It showed that organic carbon had no significant effect on the abundance of Nitrosomomas and Candidutus_Kuenenia, while increasing the abundance of Candidutus_Brocadia and Denitratisoma in the sludge. This study provides ideas for the rapid start of continuous flow CANON granular sludge process to treat wastewater with low C/N ratio.

[Impact of Hydraulic Retention Time on Performance of Partial Nitrification Granular Sludge in Continuous Stirred-Tank Reactor].

The effects of different hydraulic retention time (HRT) on short-cut nitrification granular sludge were studied in a continuous stirred-tank reactor (CSTR) by maintaining stable influent ammonia nitrogen load. Particle size distribution, extracellular polymeric substances (EPS), and functional bacterial kinetics were analyzed. The morphology of granular sludge, the performance of the CSTR, and the activity of functional microorganisms were investigated. The high throughout sequencing technology of MiSeq was employed to analyze the structure of the microbial community in sludge. The results showed that the ammonia nitrogen removal rate in the reactor was gradually increased from 80% to 95%, and the nitrite accumulation rate was always over 85% when the HRT was decreased from 4 h to 1 h. Particle size distribution of granular sludge was greatly influenced by HRT. The mass fraction of granules with a diameter smaller than 0.3 mm and larger than 1.6 mm was gradually declined, whereas the mass fraction of granules with a diameter between 0.3 mm and 0.8 mm was increased when HRT was shortened from 4 h to 1 h. The dominating proportion of granules with a diameter between 0.3 mm and 0.8 mm reached about 50% when HRT was 1 h. The impact of HRT on the activity of functional microorganisms was studied, and HRT activity was found to be closely related to the size of granular sludge. Proteobacteria were dominant in the system. AOB enrichment was represented by Nitrosomonas, which was more than 56%. Shortening HRT is beneficial for the enrichment of AOB.

Reversible luminescence switching of NaYF4:Yb,Er nanoparticles with controlled assembly of gold nanoparticles.

Upon the tunable surface plasmon band of the pH-induced reversible assembly of gold nanoparticles mediated by cysteine, the manipulation of green and red upconversion emission, and the switching of the red emission of the NaYF(4):Yb,Er nanoparticles have been achieved in a facile and reproducible way.

HHIP overexpression inhibits the proliferation, migration and invasion of non-small cell lung cancer.

OBJECTIVE: The primary purpose of this study is to investigate the effect of hedgehog-interacting protein (HHIP) overexpression on the proliferation, migration and invasion of non-small cell lung cancer (NSCLC). METHODS: Firstly, HHIP gene expression data of NSCLC tissues and normal tissues were obtained from GSE18842/GSE19804/GSE43458 databases of the Gene Expression Omnibus (GEO) database and then validated by TCGA NSCLC database in a cohort of 1027 cases of NSCLC patients and 108 cases of normal people. A chi-square test was used to analyze the relationship between HHIP expression and clinicopathological characteristics of NSCLC. The expression levels of HHIP in NSCLC cells were detected by quantitative-real time PCR. The function of HHIP was investigated by a series of in vitro assays. CCK-8, wounding healing, Transwell invasion assay were utilized to explore the mechanisms of HHIP. RESULTS: HHIP mRNA were significantly down-regulated in NSCLC in three GEO databases and TCGA database (P<0.05). This result was confirmed in NSCLC cell lines by qRT-PCR analysis, its expression in normal NSCLC cell line BEAS-2B was significantly higher than that in NSCLC cells. Chi-square test results showed that the low expression of HHIP was correlated with gender, cancer type, TNM stage and tumor size. Functional experimental results showed that over-expressing HHIP significantly decreased the ability of cell proliferation, migration and invasion in NSCLC cells (P<0.05). CONCLUSION: Overall, the above results indicated that HHIP could regulate proliferation, migration and invasion, and could be used as a judging criterion for identifying NSCLC classification and stage.

[Start-up Performance and Sludge Characteristics of Single-stage Autotrophic Nitrogen Removal System with Granular Sludge at Low Ammonia Nitrogen Concentration at Room Temperature].

The start-up and stable operation of single-stage autotrophic nitrogen removal process under low ammonia nitrogen substrate at room temperature appears as the premise and basis for the application in municipal wastewater treatment. In this study, the PN/A (partial nitritation and ANAMMOX) granular sludge for long-term storage was inoculated into an air-lift bioreactor to investigate the nitrogen removal performance during the start-up of single-stage partial nitritation and ANAMMOX process under the following conditions:temperature at (23±2)℃, pH at 7.7-8.0. Synthetic wastewater with ammonia nitrogen concentration of 70 mg·L-1 was used as influent. By stepwise shortening hydraulic retention time (HRT) (1.1 h→0.9 h→0.7 h→0.5 h) and increasing ammonia nitrogen loading rate[1.53 kg·(m3·d)-1→1.87 kg·(m3·d)-1→2.40 kg·(m3·d)-1→3.36 kg·(m3·d)-1], the bioactivity as the synergy between the ammonia oxidizing bacteria (AOB) and anaerobic oxidizing bacteria (AMX) were gradually restored. After 95 d operation and regulation, the process was successfully established and the removal rate of NH4+-N and TN were 85% and 69%, respectively. According to the performance of sludge at each stage, the nitrite oxidizing bacteria (NOB) were selectively inhibited by controlling dissolved oxygen strictly. The average particle size gradually increased and finally was reached to 1.30 mm after the sludge was adapted to the environment. The profile of the mature autotrophic granular sludge was smooth and clear, SEM showed that the center of granular sludge formed a cavity with porous structure on the surface, the sludge morphology consisted mainly of cocci, with a small amount of bacilli and short bacilli. The major component of EPS in granular sludge was protein (81.48%) indicating that it had a good settling performance.

[Start-up of a Three-stage PN/A Granular Sludge Reactor for Treating Wastewater with High Concentrations of Ammonia].

In order to apply partial nitritation-ANAMMOX (PN/A) technology to treat wastewater with high concentrations of ammonia, autotrophic nitrogen-removing granular sludge was crushed and inoculated into a three-stage continuous flow reactor. The nitrogen loading rate (NLR), dissolved oxygen (DO) concentration, and free ammonia (FA) levels in each compartment of the reactor were controlled over a 106-day period. Results showed that the nitritation process occurred with the inoculated granules during the initial phase. A limited aeration strategy was employed in the reactor at relatively high NLRs. Given the effective suppression of nitrite-oxidizing bacteria and the prevention of ANAMMOX bacteria from high DO conditions, the compact structure and nitrogen-removal activity of the granules could be improved. When the ammonia-nitrogen concentration was increased in the influent to 350 mg·L-1, the adverse impacts of high FA concentrations on the functional microbe activity in the first compartment should be eliminated. This occurs by reducing the influent pH and alkalinity dosage. This occurs by reducing the influent pH and degree of alkalinity. As a result, a total nitrogen removal rate of 7.2 kg·(m3·d)-1 was achieved in the reactor, which is 50 to 100 times higher than that of conventional activated sludge systems. The consistent improvement in the nitrogen-removal activity of the granules was demonstrated by batch testing at different aeration intensities. This showed that activity was greatest in the first compartment, which showed the highest granular maturity. In addition, a clear linear correlation (R2>0.97) was observed between the amount of extracellular polymeric substance and the specific nitrogen removal rate. This indicated that the dense granules played a positive role in enhancing the performance of the reactor.

[Effects of Environmental Factors on the Synergy of Functional Bacteria in Completely Autotrophic Granular Sludge].

To obtain experimental evidences for optimizing a completely autotrophic nitrogen removal process based on granules, the effects of dissolved oxygen (DO) concentration, temperature (t), initial ammonium (NH4+-N) concentration, and solution pH conditions on the synergy between the aerobic and anaerobic ammonium-oxidizing bacteria (AOB and AMX) were investigated using a single factor batch experiment, while the analysis of the microbial community structure within them was conducted using MiSeq high-throughput pyrosequencing. Results revealed that AOB (genus Nitrosomonas) and AMX (genus Candidatus Kuenenia) dominated in the granules, representing relative abundances of 32.9% and 9.8%, respectively. For the granules, the highest specific nitrogen removal rate of q(TN)=(17.7±1.0) mg·(g·h)-1 was obtained at a DO concentration of 2 mg·L-1, while the initial NH4+-N concentration was set at 100 mg·L-1. And a lower DO level resulted in partial nitritation became the rate-limiting step of process, otherwise, it would be the ANAMMOX reaction instead. According to the free energy of the reactions, the activity of AMX was more sensitive to low temperature than that of AOB. When the reaction temperature was lower than 30℃, nitrite accumulation could be observed in bulk liquid, with the significant decrease of q(TN) for the granules. Under the same oxygen supply conditions, an initial NH4+-N concentration lower than 100 mg·L-1 could inhibit the activity of AMX partly. However, with an initial NH4+-N concentration over 150 mg·L-1, either oxygen-limiting or high free ammonia concentration could lead to the dramatic decrease of q(TN). In addition, the effective synergy of the two types of ammonium oxidizers in granules was always achieved at solution pH in the range of 7.0-8.5.