[Multicenter evaluation of the diagnostic efficacy of jaundice color card for neonatal hyperbilirubinemia].

Objective: To evaluate the diagnostic efficacy and practicality of the Jaundice color card (JCard) as a screening tool for neonatal jaundice. Methods: Following the standards for reporting of diagnostic accuracy studies (STARD) statement, a multicenter prospective study was conducted in 9 hospitals in China from October 2019 to September 2021. A total of 845 newborns who were admitted to the hospital or outpatient department for liver function testing due to their own diseases. The inclusion criteria were a gestational age of ≥35 weeks, a birth weight of ≥2 000 g, and an age of ≤28 days. The neonate's parents used the JCard to measure jaundice at the neonate's cheek. Within 2 hours of the JCard measurement, transcutaneous bilirubin (TcB) was measured with a JH20-1B device and total serum bilirubin (TSB) was detected. The Pearson's correlation analysis, Bland-Altman plots and the receiver operating characteristic (ROC) curve were used for statistic analysis. Results: Out of the 854 newborns, 445 were male and 409 were female; 46 were born at 35-36 weeks of gestational age and 808 were born at ≥37 weeks of gestational age. Additionally, 432 cases were aged 0-3 days, 236 cases were aged 4-7 days, and 186 cases were aged 8-28 days. The TSB level was (227.4±89.6) µmol/L, with a range of 23.7-717.0 µmol/L. The JCard level was (221.4±77.0) µmol/L and the TcB level was (252.5±76.0) µmol/L. Both the JCard and TcB values showed good correlation (r=0.77 and 0.80, respectively) and agreements (96.0% (820/854) and 95.2% (813/854) of samples fell within the 95% limits of agreement, respectively) with TSB. The JCard value of 12 had a sensitivity of 0.93 and specificity of 0.75 for identifying a TSB ≥205.2 µmol/L, and a sensitivity of 1.00 and specificity of 0.35 for identifying a TSB ≥342.0 µmol/L. The TcB value of 205.2 µmol/L had a sensitivity of 0.97 and specificity of 0.60 for identifying TSB levels of 205.2 µmol/L, and a sensitivity of 1.00 and specificity of 0.26 for identifying TSB levels of 342.0 µmol/L. The areas under the ROC curve (AUC) of JCard for identifying TSB levels of 153.9, 205.2, 256.5, and 342.0 µmol/L were 0.96, 0.92, 0.83, and 0.83, respectively. The AUC of TcB were 0.94, 0.91, 0.86, and 0.87, respectively. There were both no significant differences between the AUC of JCard and TcB in identifying TSB levels of 153.9 and 205.2 µmol/L (both P>0.05). However, the AUC of JCard were both lower than those of TcB in identifying TSB levels of 256.5 and 342.0 µmol/L (both P<0.05). Conclusions: JCard can be used to classify different levels of bilirubin, but its diagnostic efficacy decreases with increasing bilirubin levels. When TSB level are ≤205.2 µmol/L, its diagnostic efficacy is equivalent to that of the JH20-1B. To prevent the misdiagnosis of severe jaundice, it is recommended that parents use a low JCard score, such as 12, to identify severe hyperbilirubinemia (TSB ≥342.0 µmol/L).

Cannabinoid receptor 2 activation alleviates septic lung injury by promoting autophagy via inhibition of inflammatory mediator release.

Septic lung injury is one of main causes of high mortality in severe patients. Inhibition of excessive inflammatory response is considered as an effective strategy for septic lung injury. Previous studies have shown that cannabinoid receptor 2 (CB2), a G protein-coupled receptor, play an important role in immunosuppression. Whether CB2 can be used as a therapeutic target for septic lung injury is unclear. The aim of this study is to explore the role of CB2 in sepsis and its potential mechanism. In this study, treatment with HU308, a specific agonist of CB2, could reduce lung pathological injury, decrease the level of inflammatory cytokines and strengthen the expression of autophagy-related gene after cecal ligation puncture (CLP)-induced sepsis in mice. Similar results were obtained in RAW264.7 macrophages after LPS treatment. Furthermore, the effect of HU308 could be blocked by autophagy blocker 3-MA in vivo and in vitro. These results suggest that CB2 serves as a protective target for septic lung injury by decreasing inflammatory factors, which is associated with the enhancement of autophagy.

MiR-203 regulates DJ-1 expression and affects proliferation, apoptosis and DDP resistance of pancreatic cancer cells.

OBJECTIVE: DJ-1 is a negative regulator of PTEN and plays a role in tumorigenesis. Abnormal miR-203 expression is associated with pancreatic cancer. Bioinformatics analysis showed a targeted relationship between miR-203 and DJ-1 3'-UTR. This study investigated whether miR-203 regulates DJ-1 expression and its role in pancreatic cancer cell proliferation, apoptosis, and cisplatin (DDP) resistance. MATERIALS AND METHODS: The Dual-Luciferase reporter gene assay validated the targeted regulation between miR-203 and DJ-1. The DDP-resistant cell line SW1990/DDP was established and divided into miR-NC group and miR-203 mimic group followed by analysis of the expression of DJ-1, PTEN and p-AKT, cell apoptosis, and proliferation. RESULTS: There was a targeted relationship between miR-203 and DJ-1 mRNA. The expression of miR-203 in SW1990/DDP cells was significantly lower than that in SW1990 cells, while the expression of DJ-1 mRNA and protein was significantly higher than that in SW1990 cells. Compared with miR-NC group, the expression of DJ-1 and p-AKT protein in SW1990/DDP cells was significantly decreased in miR-203 mimic transfection group, while the expression of PTEN was significantly increased with increased cell apoptosis and decreased cell proliferation, as well as reduced DDP resistance. CONCLUSIONS: The decreased expression of miR-203 and the increased expression of DJ-1 is associated with drug resistance in pancreatic cancer cells. Elevated miR-203 can inhibit the expression of DJ-1, affect the activity of PTEN-PI3K/AKT pathway, inhibit the proliferation of pancreatic cancer cells, induce cell apoptosis, and reduce DDP resistance of pancreatic cancer cells.

Global cooling and enhanced Eocene Asian mid-latitude interior aridity.

Tibetan Plateau uplift has been suggested as the main driving force for mid-latitude Asian inland aridity (AIA) and for deposition of thick aeolian sequences in northern China since the Miocene. However, the relationship between earlier AIA and Tibetan Plateau mountain building is uncertain because of a lack of corresponding thick aeolian sequences with accurate age constraints. We here present results for a continuous aeolian sequence that spans the interval from >51 to 39 Ma from the eastern Xorkol Basin, Altun Shan, northeastern Tibetan Plateau. The basal age of the studied sequence postdates initial uplift of the Tibetan Plateau by several million years. Our results indicate that the local palaeoclimate was teleconnected strongly to the overall global cooling pattern, so that local enhanced aridification recorded by the studied aeolian sequence is dominantly a response to global climatic forcing rather than plateau uplift.

[Clinical effect of polyvinyl alcohol particles combined with chemoembolization in treatment of hepatocellular carcinoma complicated by hepatic arteriovenous shunt and related and prognostic factors].

Objective: To investigate the clinical effect of polyvinyl alcohol (PVA) particles combined with chemoembolization using chemotherapeutic agents or chemotherapeutic agents lipiodol emulsion (CALE) in the treatment of hepatocellular carcinoma (HCC) complicated by hepatic arteriovenous shunt (HAVS) and related prognostic factors. Methods: A retrospective analysis was performed for the clinical data of 133 patients with HCC complicated by HAVS. HAVS was classified into slow-flow HAVS, intermediate-flow HAVS, and high-flow HAVS, which were treated with 300-500µm, 500-710µm, and 710-1000µm PVA particles, respectively. The patients with slow-flow and intermediate-flow HAVS underwent embolization with PVA combined with chemotherapeutic agents followed by CALE, while those with high-flow HAVS underwent the treatment with PVA combined with chemotherapeutic agents alone. The survival time, progression-free survival time, and postoperative complications were followed up and analyzed. The Kaplan-Meier method was used to calculate cumulative survival rate and the Cox proportional hazards model was used to determine prognostic factors. Results: The median overall survival (OS) of 133 patients was 9.1 months, and the 6-, 12-, and 24-month survival rates were 73.7%, 36.2%, and 10.2%, respectively. The median OS of slow-flow group (36 patients), intermediate-flow group (58 patients), and high-flow group (39 patients) were 7.3, 9.1, and 10.8 months, respectively. And the 6- and 12-month survival rates were 69.2%/19.0%, 72.4%/39.2%, and 77.8%/42.7%, respectively. There was no significant difference in survival time between the patients with different types of HAVS (χ2= 2.865,P= 0.239). The incidence rates of postoperative gastroesophageal variceal bleeding and acute liver failure were 1.1% and 0.4%, respectively. The results of Cox regression analysis showed that preoperative alpha-fetoprotein level≥400 ng/ml (HR= 2.105,P= 0.006) was an independent risk factor, while multiple embolizations (HR= 0.482,P= 0.011), tumor remission (HR= 0.431,P= 0.041), and multimodality therapy (HR= 0.416,P= 0.004) were independent protective factors. Conclusion: PVA particles combined with chemotherapeutic agents or CALE is safe and effective in the treatment of HCC complicated by HAVS. Patients with multiple embolizations, tumor remission, and multimodality therapy tend to have good prognosis, while those with a high level of alpha-fetoprotein before embolization often have poor prognosis.

Erythropoietin pretreatment exerts anti-inflammatory effects in hepatic ischemia/reperfusion-injured rats via suppression of the TLR2/NF-κB pathway.

INTRODUCTION: The inflammatory response plays an important role in liver dysfunction after hepatic ischemia/reperfusion (I/R), which is tightly regulated by the Toll-like receptor 2 (TLR2)/nuclear factor (NF)-κB pathway; suppression of TLR2/NF-κB signaling has therefore become a promising target for anti-inflammatory treatment in hepatic I/R injury. Erythropoietin (EPO) is a glycoprotein cytokine produced primarily by the kidney that has anti-inflammatory activities. The purpose of the present study was to investigate the effect of EPO preconditioning, if any, against hepatic I/R injury in rats and its underlying mechanisms. MATERIALS AND METHODS: Male Sprague-Dawley rats were subjected to partial (70%) hepatic ischemia for 45 minutes after pretreatment with either saline or EPO followed by 24-hour reperfusion. Hepatic injury was evaluated according to biochemical and histopathologic examinations. The expression of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), and interleukin-6 (IL-6) were measured by using enzyme-linked immunosorbent assay and real-time polymerase chain reaction. The expression of nuclear translocation and phosphorylation of NF-κB p65, EPOR receptor (EPOR), p-EPOR, p-IκB-α, IκB-α, and TLR2 were determined by using Western blot analysis. RESULTS: EPO treatment significantly improved hepatic function and histology, as indicated by reduced transaminase levels and pathologic changes. The expression of TNF-α, IL-1ß, IL-6, p-IκB-α, and TLR2 was significantly decreased with up-regulation of p-EPOR by EPO. Moreover, EPO pretreatment also reduced I/R-induced the phosphorylation and nuclear translocation of NF-κB p65 subunits in liver tissue, but EPO had no influence on the expression of p65 and IκB-α. CONCLUSIONS: These results suggest that EPO pretreatment ameliorates hepatic I/R injury, which is involved in suppressing TLR2/NF-κB-mediated inflammation.

Anti-erythropoietin receptor antibodies in systemic lupus erythematosus patients with anemia.

Anemia is a common hematologic abnormality in systemic lupus erythematosus (SLE). An inadequate erythropoietin (EPO) response in SLE patients with anemia has been described that may be due to the presence of antibodies to EPO in SLE patients. However, whether anemia in patients with SLE is related to antibodies to EPO receptor (EPOR) has not yet been investigated. We enlisted 169 consecutive patients with SLE and 45 normal individuals to investigate the existence and importance of circulating autoantibodies to EPOR in sera from patients with SLE. In all patients with SLE, the disease activity was evaluated by using the SLE disease activity index SLEDAI. Anti-EPOR antibodies were detected by using an enzyme-linked immunosorbent assay (ELISA). A higher frequency of anti-EPOR antibodies was observed in SLE patients than in healthy controls (18.3% vs 2.2%, p = 0.007). Moreover, anti-EPOR antibodies were detected in 22 of 69 (31.9%) SLE patients with anemia and in only nine of 100 (9.0%, p < 0.001) in those without. Furthermore, the patients with anti-EPOR antibodies exhibited more severe anemia and often presented as microcytic anemia (p = 0.001). Finally, anti-EPOR antibodies seemed more likely to occur in patients with rash (p = 0.008), lower levels of C(3) component (p = 0.01), higher titer of anti-dsDNA antibodies (p < 0.001) and higher disease activity scores (p = 0.024). The results of this study suggest that anti-EPOR antibodies might play a vital role in SLE patients developing anemia because of the higher incidence of antibodies to EPOR found in SLE patients with anemia. Thus, there might be clinical value in detecting anti-EPOR antibodies in SLE patients with anemia. Therefore, the pathologic role of the antibodies in inducing anemia needs to be established in future studies.

A meta-analysis and systematic review of prophylactic endoscopic treatments for postpolypectomy bleeding.

PURPOSE: The aim of this meta-analysis and systematic review was to determine whether bleeding prophylaxis benefits patients after colonoscopic polypectomy. METHODS: A systematic review of the literature was performed to find prospective randomized controlled trials of postpolypectomy hemorrhage prophylaxis. Studies were selected according to specific criteria and analyzed to generate pooled data. RESULTS: Eight studies encompassing 2,595 polyps met the criteria for the meta-analysis. The rate of early bleeding was significantly decreased relative to the control when a single prophylactic technique was used [2.58% vs. 8.15%, OR = 0.34 (95% CI, 0.20-0.58), P < 0.0001]. The use of multiple prophylactic techniques resulted in a lower early postpolypectomy hemorrhage rate compared with the use of a single prophylactic technique [0% vs. 8.41%, OR = 0.12 (95% CI, 0.03-0.47), P = 0.002]. The late bleeding rate did not differ significantly between the monotherapy and control groups [0.61% vs. 1.39%, OR = 0.37 (95% CI, 0.11-1.28), P = 0.12], and the use of combined preventative techniques did not significantly decrease the late postpolypectomy bleeding (PPB) rate compared with use of a single prophylactic method [1.43% vs. 2.05%, OR = 0.70 (95% CI, 0.32-1.55), P = 0.38]. CONCLUSION: Prophylactic endoscopic treatments are effective at reducing early PPB after colonoscopic polypectomy. However, patients with late PPB may not benefit from bleeding prophylaxis.

The differences between American and Chinese patients with Crohn's disease.

AIM: The effect of race on Crohn's disease (CD) remains uncertain. This study compared the characteristics of American white patients and Chinese patients with CD. METHOD: A retrospective chart review was conducted for patients who required management of colorectal CD between 1985 and 2004 at either Cleveland Clinic Florida (CCF) or at the 301 Hospital in China. Data included a family history of CD, smoking history, location of the CD and histopathology. RESULTS: The mean age of onset in the 153 patients was 29.8 ± 16.4 years for American white patients and 32.4 ± 15.3 years for Chinese patients (not significant). Sixty per cent of American white patients were women vs 37% of Chinese patients (P = 0.003). Twelve per cent of American white patients vs 1% of Chinese patients had a family history of CD (P = 0.016). American white patients had significantly higher rates of arthritis (32%vs 4%), abscess (19%vs 0%), rectal and perineal fistula (52%vs 0%), and disease involving the colon and rectum when compared with Chinese patients (all P < 0.05). American white patients had more colorectal sites involved and higher rates of extraintestinal diseases (40%vs 20%) than Chinese patients (all P < 0.05). Chinese patients had higher rates of ileocaecal disease (82%vs 52%) and deep ulcers (66%vs 24%) in the colorectum (all P < 0.001). There were no statistical differences in the incidence of smoking, perforation, intra-abdominal fistula, stenosis, bowel obstruction, toxic megacolon or granuloma formation. CONCLUSION: This study found that colorectal CD had a more severe clinical presentation and pathological involvement in American white patients than in Chinese patients.

Short communication: responses to increasing amounts of free alpha-linolenic acid infused into the duodenum of lactating dairy cows.

Increasing the alpha-linolenic acid (LNA; 18:3 cis-9,cis-12,cis-15) content of milk fat might help promote consumers' health. The objective of this study was to determine the potential to alter the content of LNA in milk by duodenal infusion of a free fatty acid mixture rich in LNA. Four multiparous lactating Chinese Holstein cows fitted with duodenal cannulas were administered 2 treatments in a crossover design: an LNA-rich fatty acid infusion at varying concentrations (0, 40, 80, 120, and 160 g/d) versus a basal infusate control. Dry matter intake was not affected by LNA infusions. Milk production tended to decrease and was quadratically affected as LNA infusion increased, but 4% fat-corrected milk yield was not changed. Milk fat content tended to increase linearly with LNA infusion. Milk protein content was not changed by LNA infusion, whereas milk lactose content and yield were decreased quadratically as LNA infusion increased. Increasing the amount of LNA infused into the duodenum linearly increased concentrations of 18:3 cis-9,cis-12,cis-15 (0.61 to 25.4 g/100g of total fatty acids) and 18:2 cis-9,cis-12 in milk fat. Increasing LNA decreased the percentages of 4:0, 14:0, and 16:0 fatty acids linearly. Increasing LNA also linearly decreased the percentages of 18:1 cis-9 and 18:2 cis-9,trans-11 in milk fat. Milk fat content of 20:5 cis-5,cis-8,cis-11,cis-14,cis-17 was quadratically affected, whereas concentrations of 18:0, 18:1 trans-9, 18:1 trans-11, and 18:2 trans-10,cis-12 were not affected. Increasing the supply of 18:3 cis-9,cis-12,cis-15 to the small intestine linearly increased 18:3 cis-9,cis-12,cis-15 in milk fat and markedly altered milk fat composition.

Toxicity effect of phenol on aerobic granules.

Aerobic granular sludge cultivated in a pilot-scale sequencing batch reactor, through mechanical separation using metal sieves, was categorized into five size categories of0.09 (flocs), 0.35, 0.82, 1.65 and 2.54 mm in mean diameter. Granule microbial activiy of each size category and the activity of the sludge flocs were determined after exposure to phenol (0-3000 mg L(-1)) at various exposure times of 4, 12, and 24 hours. The microbial activity reduction follows a linear relationship with the increase in phenol concentration for both granules and sludge flocs. The C50 value, i.e., the phenol concentration causing 50% inhibition of the microbial activity, decreased significantly with the exposure time, but it increased with granule size. The C50 increased by 18% from 1273 mg L(-1) for sludge flocs to 1497 mg L(-1) for granules of size 2.54 mm at an exposure time of 24 hours. The results indicated that the granular structure could protect the microbial cells from phenol toxicity. The application of aerobic granules in wastewater treatment could provide an improved ability to tolerate toxic chemical shock, particularly at longer exposure times.

Startup of pilot-scale aerobic granular sludge reactor by stored granules.

The startup of a pilot-scale aerobic granular sludge reactor was investigated by seeding with 4-month stored aerobic granules. Two liters of granules were inoculated into the reactor (5.9% of reactor volume), which gave a biomass concentration of 1.03 g l(-1). Experimental results showed that seeding granules could be successfully maintained in the reactor. The microbial activity of seeding granules could be fully recovered to that of fresh granules after 2 days of operation, and new granules started to grow after day 5. Newly developed aerobic granules at stable period had similar size and morphology as seeding granules, and a biomass concentration of 6.0 g l(-1) was achieved in the reactor. The experiment demonstrated for the first time that stored aerobic granules could be used for easy and quick startup of aerobic granular sludge reactor.

The effect of upflow air velocity on the structure of aerobic granules cultivated in a sequencing batch reactor.

The effect of upflow air velocity on the formation and structure of aerobic granules was studied in three column sequencing batch reactors. Upflow aeration would be the major cause of hydrodynamic shear force in the column reactor. Results showed that high upflow air velocity resulted in more compact, denser, rounder, stronger and smaller aerobic granules, while high biomass retention in the reactor was achieved. It was found that high upflow air velocity could induce granular sludge to secrete more cell polysaccharides which in turn contributed to the compact and strong structure. It appears from this study that the structure of aerobic granules could be controlled by manipulating the upflow air velocity.

Growth kinetics of aerobic granules developed in sequencing batch reactors.

AIMS: This paper attempts to develop a kinetic model to describe the growth of aerobic granules developed under different operation conditions. METHODS AND RESULTS: A series of experiments were conducted by using four-column sequencing batch reactors to study the formation of aerobic granules under different conditions, e.g. organic loading rates, hydrodynamic shear forces and substrate N/COD ratios. A simple kinetic model based on the Linear Phenomenological Equation was successfully derived to describe the growth of aerobic granules. It was found that the growth of aerobic granules in terms of equilibrium size and size-dependent growth rate were inversely related to shear force imposed to microbial community, while a high organic loading favoured the growth of aerobic granules, leading to a large size granule. The effect of substrate N/COD ratio on the growth kinetics of aerobic granules was realized through change in microbial populations, and enriched nitrifying population in aerobic granules developed at high substrate N/COD ratio resulted in a low overall growth rate of aerobic granules. CONCLUSIONS: The proposed model can provide good prediction for the growth of aerobic granules indicated by the correlation coefficient >0.95. SIGNIFICANCE AND IMPACT OF THE STUDY: The kinetic model proposed could offer a useful tool for studying the growth kinetics of cell-to-cell immobilization process. The study confirmed that the growth of aerobic granules and biofilms are subject to a similar kinetic pattern. This work would also be helpful for better understanding the mechanism of aerobic granulation.

Substrate concentration-independent aerobic granulation in sequential aerobic sludge blanket reactor.

The development of aerobic granules was studied in four column-type sequential aerobic sludge blanket reactors fed with different substrate concentrations ranging from 500 to 3000 mg l(-1) COD. Results showed that aerobic granules successfully formed in all reactors fed with different substrate concentrations, indicating that the formation of aerobic granules is independent of the substrate concentration. The granule size, roundness, compactness, physical strength, as well as cell surface hydrophobicity and cell polysaccharides contents of the cultivated aerobic granules were investigated. It was shown that aerobic granules formed with different substrate concentrations had similar roundness and compactness. However, the size of aerobic granules slightly increased with an increase in substrate concentration, while granule strength decreased with substrate concentration. It was found that there was a significant increase in cell surface hydrophobicity and cell polysaccharides of the aerobic granules compared to that of seed sludge. The high cell surface hydrophobicity and high cell polysaccharides contents were believed to play an important role in the formation of aerobic granules. However, substrate concentration seems not to be a governing factor for the formation of aerobic granules. The results of this study would be useful for developing aerobic granules-based bioreactor and for better understanding of the mechanism of aerobic granulation. It was also clearly demonstrated that aerobic granules-based bioreactor would have great potential in the treatment of high-strength wastewater.

Biomass and porosity profiles in microbial granules used for aerobic wastewater treatment.

AIMS: To obtain biomass and porosity profiles for aerobically grown granules of different diameters and to determine a suitable range of granule diameters for application in wastewater treatment. METHODS AND RESULTS: Microbial granules were cultivated in an aerobic granulated sludge reactor with model wastewaters containing acetate, or ethanol plus acetate, or glucose as the main carbon source. Granules were formed by retaining microbial aggregates using a settling time of 2 min. Sampled granules had diameters ranging from 0.45 to 3 mm. Microbial biomass in the granules was detected with the nucleic acid stain SYTO 9 and confocal laser scanning microscopy. The thickness of the microbial biomass layer was proportional to the granule diameter, and had a maximum value of 0.8 mm. The thickness of the microbial biomass layer correlated with the penetration depth of 0.1 microm fluorescent beads into the granule. CONCLUSIONS: The microbial biomass and porosity studies suggest that aerobically grown microbial granules should have diameters less than a critical diameter of 0.5 mm, if deployed for wastewater treatment applications. This critical diameter is based on the assumption that whole granules should have a porous biomass-filled matrix. SIGNIFICANCE AND IMPACT OF THE STUDY: This work could contribute to the development of aerobic granulation technology for effective biological wastewater treatment.

Aerobic granulation in sequential sludge blanket reactor.

Aerobic granulation was studied in a column-type of sequential sludge blanket reactor. Reactor was operated 4 hours per cycle under a chemical oxygen demand (COD) loading rate of 6.0 kg/m3/d by using acetate as substrate. Results showed that aerobic granules with a mean diameter of 0.35 mm were observed at cycle 42. With granulation proceeding, the sludge volume index (SVI) value gradually decreased, and to an average value of 50 mL/g at stable granulation period. Observation of granules' microstructure by scanning electron microscopy (SEM) showed that rod bacteria were dominant in granules with lots of cavities presented. An increase in cell hydrophobicity was observed after the appearance of aerobic granules. The cell hydrophobicity of sludge was found to be about 50% higher after granulation. It appears that high hydrophobicity could induce cell attachment and further strengthen cell-cell interaction; cell hydrophobicity might therefore play a major role in the formation of aerobic granules.

Characteristics of aerobic granules grown on glucose and acetate in sequential aerobic sludge blanket reactors.

Aerobic granules were cultivated in two column-type sequential aerobic sludge blanket reactors fed with glucose and acetate, respectively. The characteristics of aerobic granules were investigated. Results indicated that the glucose- and acetate-fed granules have comparable characteristics in terms of settling velocity, size, shape, biomass density, hydrophobicity, physical strength, microbial activity and storage stability. Substrate component does not seem to be a key factor on the formation of aerobic granules. However, microbial diversity of the granules is closely associated with the carbon sources supplied to the reactors. Compared with the conventional activated sludge flocs, aerobic granules exhibit excellent physical characteristics that would be essential for industrial application. This research provides a complete set of characteristics data of aerobic granules grown on glucose and acetate, which would be useful for further development of aerobic granules-based compact bioreactor for handling high strength organic wastewater.

The effects of shear force on the formation, structure and metabolism of aerobic granules.

The effect of shear force on aerobic granulation was studied in four column-type, sequential aerobic sludge blanket reactors. Hydrodynamic turbulence caused by upflow aeration served as the main shear force in the systems. Results showed that aerobic granulation was closely associated with the strength of shear force. Compact and regular aerobic granules were formed in the reactors with a superficial upflow air velocity higher than 1.2 cm s(-1). However, only typical bioflocs were observed in the reactor with a superficial upflow air velocity of 0.3 cm s(-1) during the whole experimental period. The characteristics of the aerobic granules in terms of settling ability, specific gravity, hydrophobicity, polysaccharide and protein content and specific oxygen utilization rate (SOUR) were examined. It was found that the shear force has a positive effect on the production of polysaccharide, SOUR, hydrophobicity of cell surface and specific gravity of granules. The hydrophobicity of granular sludge is much higher than that of bioflocs. Therefore, it appears that hydrophobicity could induce and further strengthen cell-cell interaction and might be the main force for the initiation of granulation. The shear-stimulated production of polysaccharides favors the formation of a stable granular structure. This research provides experimental evidence to show that shear force plays a crucial role in aerobic granulation and further influences the structure and metabolism of granules.